CLIMATE CHANGE and 

EXTREME HEAT EVENTS

 1

Contents

Overview ......................................................................................................................................................2

Understanding Extreme Heat Events.............................................................................................................3

What Is an Extreme Heat Event? ............................................................................................................3

Health Effects of Extreme Heat Events ...................................................................................................4

Vulnerability to Extreme Heat Events.....................................................................................................5

Climate Change and Extreme Heat Events....................................................................................................6

Climate Change and a Warming World..................................................................................................6

Future Climate Change..........................................................................................................................7

Extreme Heat Events Will Become More Frequent and More Severe......................................................8

Projected Health Impacts of Extreme Heat Events in the Future...........................................................10

Responding to Extreme Heat Events ...........................................................................................................11

Extreme Heat Programs: Working to Protect Public Health..................................................................11

How Do Extreme Heat Programs Perform? ..........................................................................................11

Conclusion..................................................................................................................................................13

More Extreme Heat Events Will Increase Need for Public Health Programs. ........................................13

All scientific information in this document is derived from peer-reviewed assessments, including those 

published by the United States Global Change Research Program and the Intergovernmental Panel

on Climate Change, from other peer-reviewed literature, or from federal government agencies.
2 Climate Change and Extreme Heat Events

Overview

Extreme heat events pose a serious danger to people throughout the United States. Studies conducted by the 

Centers for Disease Control and Prevention (CDC) have shown that exposure to extreme heat can increase 

discomfort and fatigue, cause heat cramps, and increase emergency room visits and hospitalizations.1 It can 

also kill. From 1999 through 2009, extreme heat exposure caused or contributed to more than 7,800 deaths 

in the United States (Kochanek et al, 2011).

Extreme heat is a real danger to human health that will become worse with time. Experts project that as our 

climate changes, extreme heat events in the United States will become more frequent, longer lasting, and 

more severe.2,3 By the end of this century, extremely high temperatures that currently occur once every

20 years could happen as often as every two to four years.2

Learning about how to prepare for and respond to extreme heat events will help protect our 

communities, especially the most vulnerable populations, from avoidable death and hardship.

This document 

describes extreme

heat events, how

an extreme heat 

event threatens 

public health, and 

how to prepare for 

and respond to such 

an event. It explains 

how the frequency, 

duration, and severity 

of extreme heat 

events are increasing 

as a result of climate 

change, and includes 

links to local programs 

and real-world 

examples from across 

the country.

RARE HEAT EVENTS WILL BECOME MORE COMMON

By the end of this century, an extreme heat event that currently occurs 

once every 20 years could occur every two to four years in most parts 

of the country. This example is based on how the climate is expected 

to change under a high greenhouse gas emissions scenario (A2; see 

page 7 for a description of scenarios).2 
 3

Understanding Extreme Heat Events

What Is an Extreme Heat Event?

While there is no single agreed upon definition of an extreme heat event, most definitions refer to an 

extended period of time (several days or more) with unusually hot weather conditions that potentially can 

harm human health.5

The U.S. Environmental Protection Agency defines extreme 

heat events as “periods of summertime weather that are 

substantially hotter and/or more humid than typical for a given 

location at that time of year.”4

One of the most severe extreme heat events in recent U.S. history occurred in July 1995 in Chicago. 

During this event, the extended increase in daily maximum temperatures (black line) as compared 

to the average for 1990-2000 (blue line) had an estimated result of more than 650 deaths.3

500

450

DEATHS 400

350

 OF DAILY 300 ER

250

NUMB 200

150

100

1-Jul 6-Jul 11-Jul 16-Jul 21-Jul 26-Jul 31-Jul

DATE

110°

105°

100°

95°

90°

85°

80°

TEMPERATURE (°F)

75°

70°

Mortality, 1995 Mortality average, 1990-2000 

Daily max temp (°F), 1995 Daily max temp (°F) average, 1990-2000

EXTREME HEAT EVENT: CHICAGO, JULY 1995
4 Climate Change and Extreme Heat Events

Heat waves can be deadly. Extreme heat was the leading 

cause of weather-related deaths in the United States 

from 2000 through 2009.6 From 1999 through 2009, 

extreme heat exposure caused more than 7,800 deaths 

in the United States.2

In addition to deaths, extreme heat events cause a wide 

range of other health problems such as rashes, cramps, 

heat exhaustion, and heat stroke. Extreme heat can also 

make existing medical conditions worse. Though harder 

to count than deaths, these health conditions affect far 

more people and lead to extra emergency room visits 

and hospitalizations.3

Health Effects of Extreme Heat Events DEATHS IN THE UNITED STATES ATTRIBUTED 

TO WEATHER CONDITIONS, 2000–2009 6

Winter Storm

Cold

HEAT

Lightning

Wind

Tornado

Hurricane

Flood

5% 7% 24% 8%

9%

11% 23%

13%

Extreme heat events are a

problem around the world. For

example, in 2003, an extreme

heat event in Europe killed 14,800

people in France alone.8

EXTREME HEAT EVENTS CAUSE A RANGE OF HEALTH PROBLEMS

PROPORTION OF POPULATION AFFECTED

Extreme heat events cause health problems and can make other health problems 

worse. Mild effects are more common, but in extreme cases, people can die.7

Deaths

Require medical attention: 

emergency room/emergency 

medical services, physician 

office, clinic visit

Heat cramps, heat exhaustion, heat stroke

Mild symptoms, discomfort, subtle effects 

(e.g., skin eruptions, heat fatigue)

SEVERITY OF EFFECT
 5

URBAN HEAT ISLANDS: MAKING A BAD SITUATION WORSE 

CERTAIN CHARACTERISTICS INCREASE RISK 

FROM EXTREME TEMPERATURES

Cities can be up to 10°F warmer than surrounding rural areas and can 

maintain warmer temperatures throughout the night. Concrete and 

asphalt in cities absorb and hold heat. Tall buildings reduce potentially 

cooling air flows. Urban environments may lack trees and other 

vegetation that provide shade and increase cooling through evaporation. 

As a result, city-dwellers may experience longer and more severe 

periods of extreme heat compared to rural or suburban dwellers.2

CERTAIN CHARACTERISTICS INCREASE RISK 

FROM EXTREME TEMPERATURES

Certain personal and community characteristics increase the risk of 

experiencing health problems during an extreme heat event.4,9,10,11

DIVIDUAL CHARACT

IN

ERISTICS

Youth Advanced age

(age 0-4 years) (65+ years)

Poverty Physical impairments

Use of certain Cognitive prescription impairments medications

Social isolation 

(“shut-ins”) Homelessness

Limited community Lack of access to 

partnerships air-conditioned 

locations/shelters

Elevated crime rate No extreme heat

Increase in paved event program

surface areas and loss Poor/inappropriate of native vegetation housing construction Urban heat 

island

COMMUN

S

ITY CHAR CTERISTIC A

INCREASE IN HEALTH RISK 

DURING EXTREME HEAT EVENT

Vulnerability to Extreme Heat Events 

Everyone should take steps 

to protect themselves and their 

families’ health during an extreme 

heat event, but some people are 

more vulnerable than others. 

Young children, people aged 65 

and older, persons with certain 

disabilities, those living in poverty 

or social isolation, and the 

homeless have a much higher risk 

of heat-related health problems 

than other people living in a 

population.4,9,10,11

If current population trends 

continue, the number of 

vulnerable Americans aged 65 

and older will continue to grow.2

In addition, the number of 

people living in urban areas may 

continue to increase exposing 

more vulnerable individuals in 

the future to the “urban heat 

island” effect (see figure at 

right).2 Changes in health care, 

transportation patterns, and 

urban design could either increase

or decrease the risk, but these 

changes are harder to predict than

population trends.
6 Climate Change and Extreme Heat Events

Climate Change and Extreme Heat Events

Climate Change and 

a Warming World

The Earth is getting warmer because 

people are adding greenhouse gases, 

such as carbon dioxide and methane, 

to the atmosphere. Most of these 

gases are being released as a result

of burning fossil fuels like coal, oil, 

and natural gas. As these gases build 

up in the atmosphere, they trap extra 

heat and cause average temperatures 

to increase—a process called global 

warming.2,3,13 Warmer temperatures 

lead to many other changes in the 

atmosphere, on land, and in the 

oceans. Together, these changes are 

known as climate change.

Average temperatures around the 

world have become warmer since the 

start of the 20th century, and they 

have risen at a particularly fast rate 

during the last 50 years. Nine of the 

ten warmest years on record have 

occurred since 2000.14

Like the rest of the world, the United 

States has become warmer. The U.S. 

average temperature has risen more 

than 2.0°F over the past 50 years, 

and it is projected to rise more in the 

future.2

 Some parts of the country 

have experienced more warming than 

others (see figure).

0th century, average air temperatures have

rent amounts in different parts of the United

RATE OF TEMPERATURE CHANGE IN THE 

UNITED STATES, 1901–2008

Since the early 2

changed by diffe

States.12
 7

Future Climate Change 

Scientists expect the Earth to keep getting warmer 

in the years ahead. Their projections are based on 

past and current observations, trends in greenhouse 

gas emissions, and computer models that show how 

additional greenhouse gases in the atmosphere will 

affect average climate conditions in different parts 

of the world. Climate models project a continued 

increase in the Earth’s average temperature over 

time. The amount of warming depends on the time 

period under consideration, and the greenhouse gas 

emissions scenarios (see box below).

Because it is difficult to project 

far-off future emissions and other 

human factors that influence 

climate, scientists use a range 

of emissions scenarios using 

various assumptions about future 

economic, social, technological, 

and environmental conditions.

PROJECTED CHANGES IN GLOBAL AVERAGE TEMPERATURES FOR DIFFERENT 

GREENHOUSE GAS EMISSIONS SCENARIOS

Scientists have modeled future temperature changes based on a variety of greenhouse gas emissions 

scenarios. Each scenario is based on a set of assumptions about population trends, economic development, 

and technology—all of which affect the amount of greenhouse gases emitted over time.15 The figure shows the 

best estimate (solid line) and likely range (shaded area) of how much temperature will have changed at different 

points in time relative to the 1960–1979 average for emissions scenarios cited in various graphics throughout 

this publication.2,17
8 Climate Change and Extreme Heat Events

Extreme Heat Events Will Become More Frequent and More Severe

Scientists expect climate change 

to lead to longer, more severe, 

and more frequent extreme heat 

events. Even using different 

climate models and emissions 

scenarios, the results generally 

point to extreme heat events 

becoming worse in almost every 

regard.2,3

Duration

Increases in average temperatures 

are projected to make extreme 

heat events last longer. Under 

an emissions scenario in which 

average temperatures have risen 

6.3°F (IPCC A2 scenario), most 

Americans could expect to see 

extreme heat events lasting 10 to 20

days longer than in the past

(see page 9 first figure).3

Severity

Another effect of higher average temperatures

is more severe heat events. The likelihood of more 

hot weather and more record hot weather increases 

as average temperatures increase (see upper right 

figure).16 The box on the top of page 10 provides 

examples of how climate is projected to change

in the United States. This particular study modeled 

how summertime temperatures in New Hampshire 

and Illinois could feel in the future. Under the 

higher emissions scenario, by the late part of 

this century, people in New Hampshire would 

experience a summer climate close to the current 

norm for North Carolina, while those in Illinois 

would experience a climate like that currently 

experienced in Louisiana or Texas.

Frequency

Climate change will also cause extreme heat events 

to happen more often. Studies show that by the end of this century, the number of days with temperatures 

reaching 100°F or more is projected to increase dramatically across the United States as a result of climate 

change. What the public now considers to be an exceptional event could become routine across much of the 

country (see page 9 second figure).2

CLIMATE CHANGE PROJECTIONS GREATLY 

INCREASE NUMBER OF HOT AND EXTREMELY 

HOT DAYS ANTICIPATED FOR BOSTON

The chart shows model projections of the number of 

summer days with temperatures greater than 90°F 

in Boston, Massachusetts, under lower and higher 

emissions scenarios. The inset shows projected days 

with temperatures greater than 100°F.2,17

EXTREME HEAT EVENTS WILL BECOME MORE SEVERE

INCREASE IN AVERAGE TEMPERATURE

e Probability of Occurrenc

More hot 

weather

Less cold 

weather More record 

hot weather

When average temperatures increase, the average temperature of “hot 

weather” and “record hot weather” will become even hotter.16
 9

EXTREME HEAT EVENTS WILL LAST LONGER

+ 1.8°F

+ 3.6°F

+ 6.3°F

Days

19.5

18

16.5

15

13.5

12

10.5

9

7.5

6

4.5

3

1.5

When average temperatures increase, the longest 

extreme heat events (here, defined as the longest event 

occurring in a 20-year period) will become even longer 

than in the past (1961–1979). In the warmest scenario, 

most of the country would experience an increase

in its longest extreme heat event of 10-20 days.3

CLIMATE CHANGE PROJECTED TO INCREASE 

THE NUMBER OF 100°F DAYS

Whether using a lower or higher emissions 

scenario, the number and distribution of days 

per year over 100°F are expected to increase 

dramatically.2,17
10 Climate Change and Extreme Heat Events

CLIMATE ON THE MOVE: CHANGING SUMMERS IN NEW HAMPSHIRE AND ILLINOIS

Yellow arrows track what summers are projected to feel like under a lower emissions scenario, while red 

arrows track projections for a higher emissions scenario.2,17

Projected Health Effects of Extreme Heat Events in the Future

As temperatures rise and extreme heat events become longer, more severe, and more frequent, experts expect 

to see more health problems and deaths caused by heat. Researchers have looked at a variety of scenarios and 

models, and consistently have reached the 

same conclusions:

•	 With climate change, the number

of deaths due to extreme heat is expected 

to keep increasing over time.

•	 Higher emissions scenarios project

a more dramatic rise in heat-related 

deaths over time.

These projections are not precise. For 

example, they assume that the death rate 

associated with a particular level of extreme 

heat (such as a 100°F day in Chicago) will 

be similar to the patterns observed in the 

past. But if the relationship between heat and 

death rates changes in the future, the expected 

number of deaths might increase or decrease. 

For example, people might get more used

to extreme heat and communities might plan 

and prepare for heat more effectively. Changes 

in demographics could also affect the number 

of heat related deaths.

PROJECTED INCREASE IN HEAT-RELATED 

DEATHS IN CHICAGO

Heat-related deaths are projected to increase in Chicago 

during the 21st century. This graph shows the projected 

number of deaths per year, averaged over a three-decade 

period around 1975, 2055, and 2085, under two emissions 

scenarios. This analysis included some measures to adapt 

to the increased heat.2,17
 11

Responding to Extreme Heat Events

Extreme Heat Programs: 

Working to Protect Public 

Health

Many of the negative health effects

attributable to extreme heat events

are preventable.1,11 Many cities

throughout the United States and

abroad have successfully developed

and deployed extreme heat programs

over the past 30 years, protecting 

public health and saving lives.1,11 The 

most effective programs incorporate

a variety of elements, which are found 

in federal recommendations and 

can be adapted according to local 

conditions and needs.4,10 Protecting 

the public from extreme heat events 

also can be part of a broader process 

of planning for natural hazards and 

disaster preparedness. These efforts 

require engaging many of the same 

stakeholders, affect many of the same 

vulnerable populations, and call for 

similar types of public outreach and

education.

How Do Extreme Heat Programs Perform?

Ideally, public health officials would evaluate the effectiveness of extreme heat programs and quantify the 

number of lives saved. In reality, though, it can be difficult to judge a program’s performance, as its elements 

change over time and the number and nature of extreme heat events vary from year to year. As a result, few 

extreme heat programs in the United States have been studied in depth to determine if they are truly effective. 

However, the limited number of studies that have taken place have concluded that extreme heat programs save 

lives.3,18

Developing and implementing extreme heat programs does not have to cost a lot of money.4 Given the 

potential to save many lives for a relatively small cost, communities may benefit from establishing extreme 

heat programs as an adaptive response to the very real threat that climate change poses.

ELEMENTS OF AN EFFECTIVE EXTREME HEAT PROGRAM

•	 A written and publicly approved program plan that

identifies program partners and vulnerable populations 

•	 Clear criteria that define extreme heat events and help

to evaluate weather forecasts and conditions

•	 Coordinated outreach to public and partners, with

consistent messaging, information, and instructions via 

public broadcast, websites, email, and social media

•	 Strategic action plans that include formal check-in and

buddy systems and in-person assessments for vulnerable 

persons

•	 Strategies and recommendations for staying cool at home

and work

•	 Designated public cooling shelters

•	 Cancellation policies for outdoor activities and events

•	 Post-season reviews of program performance by partners

•	 Public input on ways to improve the program
12 Climate Change and Extreme Heat Events

KANSAS CITY, MISSOURI: 30 YEARS OF EXTREME HEAT PROGRAM 

EXPERIENCE

Kansas City developed its extreme heat program after a heat event in July, 

1980, which caused a number of deaths in the metropolitan area.

Kansas City’s program relies on numerous partnerships to help identify people 

at risk and coordinate services. The Kansas City Health Department is the lead 

agency for the city’s extreme heat program. As such, the Health Department:

•	 Assists the National Weather Service in determining whether to issue

heat-health notifications and notifies other program partners of extreme 

heat decisions.

•	 Coordinates extreme heat-related response activities.

•	 Develops and coordinates extreme heat-related public messaging, media,

and communication strategies.

•	 Collects and summarizes information on the health impacts of extreme

heat and interventions undertaken during specific events.

•	 Suggests improvements to health surveillance systems.

The Kansas City Health Department also coordinates pre-season and endof-season meetings with partners to review community plans and evaluate 

performance. At these meetings, the Health Department and its partners 

can consider recruiting additional partners to help serve difficult-to-reach 

high-risk segments of the population, such as the elderly, “shut-ins,” and the 

homeless.

Over time, the Health Department’s role has shifted from providing assessment 

and intervention services to its current role of declaring events, coordinating 

partners, and managing public information and education efforts. This new 

role keeps the program effective by leveraging partnerships to extend the 

reach of information and services to the most vulnerable people during heat 

events.
 13

Conclusion

More Extreme Heat Events Will Increase Need for Public Health Programs

Deaths and illnesses associated with extreme heat events will likely increase as more frequent, longer, and more 

severe future extreme heat events occur. There is a clear need for enhanced recognition of the public health 

challenges that future extreme heat events will pose.

Currently, effective programs offer hope that this health challenge can be met. Today, a wide range of creative 

and resourceful partnerships in locations across the country address the challenges of extreme heat events. 

As the earth continues to warm, public health officials will need to develop and implement extreme heat 

programs that are flexible enough to manage under extraordinary conditions that will become increasingly 

common.

Examples of materials that are available already for interested parties to incorporate in an extreme heat 

program are provided below.

SPECIFIC GUIDANCE FOR RESPONDING TO EXTREME HEAT EVENTS 

IS COMMON IN MANY EXTREME HEAT PROGRAMS

Many cities have developed specific tools to aid in the assessment of potential risk to populations during an extreme heat 

event or to help with the response to these conditions. Source: Baltimore City Health Department, 2009.
14 Climate Change and Extreme Heat Events

Heavy sweating 

Weakness

Cold, pale, clammy skin

Fast, weak pulse 

Nausea or vomiting 

Fainting

Extremely hot weather can cause 

sickness or even death. 

STAY COOL. Stay in air-conditioned

buildings as much as possible and

avoid direct sunlight. 

STAY HYDRATED. Drink plenty of

water and don’t wait until you’re

thirsty to drink.

STAY INFORMED. Stay updated on 

Seek medical care immediately if you have local weather forecasts so you can 

or someone you know has symptoms plan activities safely when it’s hot 

of heat sickness. Warning signs and outside. symptoms vary but may include:

KNOW WHEN IT’S HOT! 

High body temperature Sign up to receive free weather 

(104°F or higher rectally) alerts on your phone or e-mails 

Hot, red, dry or moist skin from www.weather.com/mobile

Rapid and strong pulse

Possible unconsciousness

www.cdc.gov/nceh/extremeheat

CS215352

Centers for Disease

Control and Prevention

National Center for

Environmental Health

Check on the elderly, or people aged 65 ent, check on 

years or older, to make sure they are safe eme heat ev During an extr

by staying cool, hydrated, and informed. , and neighbors at at-risk friends, family

least twice a day. Encourage them to: 

, and 

People with a chronic medical • Check on a friend or neighbor

condition are less likely to sense and have someone do the same for you. 

en to cook. v

respond to changes in temperature. Also, g the stove or o • Avoid usin

they may be taking medications that can eight, light-colored 

intensify the • Wear loose, lightw

clothing.

WHO NEEDS SPECIAL CARE?

The elderly, people with a chronic medical condition, 

children, homeless or poor, outdoor workers, and 

athletes are most at-risk to heat sickness.

FOR MORE INFORMATION

www.cdc.gov/

nceh/extremeheat

Athletes and people who exercise

in extreme heat are more likely to become 

dehydrated and are more likely to get heat 

sickness. 

• Limit outdoor activity, especially midday when it is the hottest part of the STOP day. all activity and get 

to a cool environ- • Schedule workouts and practices ment if you feel earlier or later in the day to avoid mid- faint or weak. day heat.

• Pace activity. Start ac tivities slowly and pick up 

the pace gradually. 

• Drink from two to four cups of water every hour 

while exercising. Muscle cramping may be an 

early sign of heat sickness.

air-conditioned shelter to the homeless 

or poor during times of extreme heat.

Never leave infants or

children in a parked car.

 Nor should pets be 

 left in parked cars– 

 they can 

GENERAL GUIDANCE FOR CITIZENS TO REDUCE THEIR RISK FROM EHES

People who work outdoors are more 

likely to become dehydrated and are more

likely to get heat sickness. 

• Drink from two to four cups of water 

every hour while working. Don’t wait 

until you are thirsty to drink.

• Avoid alcohol or liquids containing

large amounts of sugar. 

• Wear and reapply sunscreen as 

indicated on the package. 

• Ask if tasks can be scheduled for earlier or later 

 sickness too. in the day to avoid midday heat.

Public health agencies are increasingly providing information on appropriate extreme heat event 

responses. Source: CDC, 2011.
 15

Examples of Resources for Further extreme heat events-related Information

Understanding the Health Risks of Extreme Heat Events

Centers for Disease Control and Prevention: Heat Waves www.cdc.gov/climateandhealth/effects/heat.htm

National Weather Service: Heat Wave: A Major Summer

Killer weather.gov/os/brochures/heat_wave.shtml

National Weather Service Heat Safety weather.gov/om/heat/index.shtml

Excessive Heat – NOAAWatch noaawatch.gov/themes/heat.php

The Impact of Climate Change on Extreme Heat Eventss

Global Climate Change Impacts in the United States globalchange.gov/publications/reports/scientificassessments/us-impacts/full-report

U.S. Climate Change Science Program. Final Report, 

Synthesis and Assessment Product 4.6. Analyses of the Effects of 

Global Change on Human Health and Welfare and Human Systems

globalchange.gov/publications/reports/scientificassessments/saps/sap4-6

U.S. Climate Change Science Program. Final Report, 

Synthesis and Assessment Product 3.3. Weather and 

Climate Extremes in a Changing Climate

globalchange.gov/publications/reports/scientificassessments/saps/sap3-3

Climate Change Indicators in the United States epa.gov/climatechange/indicators.html

Guidance for Developing Extreme Heat Events Programs

Centers for Disease Control and Prevention: 

Extreme Heat: A Prevention Guide to Promote Your 

Personal Health and Safety

emergency.cdc.gov/disasters/extremeheat/

heat_guide.asp

Department of Health – United Kingdom: 

Heatwave Plan for England: Protecting Health and 

Reducing Harm from Extreme Heat and Heatwaves

dh.gov.uk/en/Publicationsandstatistics/

Publications/PublicationsPolicyAndGuidance/

DH_114430

Health Canada: Developing Heat Resilient Communities 

and Individuals in Canada

hc-sc.gc.ca/ewh-semt/climat/adapt/ 

heat-chaleur-eng.php

U.S. Environmental Protection Agency: 

Extreme Heat Events Guidebook epa.gov/heatisld/about/heatguidebook.html

World Health Organization: Heat-Health Action Plans:

Guidance

euro.who.int/__data/assets/pdf_file/0006/95919/

E91347.pdf

Examples of Local Extreme Heat Program Resources

Baltimore City Health Department: 

Code Red Heat Alert Information (homepage) baltimorehealth.org/coderedinfo.html

City of Boston: Helping the Homeless During Extremely Hot 

Weather cityofboston.gov

City of Chicago: Emergency Management and 

Communications: Weather Extremes – Extreme 

Temperatures

cityofchicago.org

City of Kansas City, Missouri: Heat Information kcmo.org/CKCMO/Depts/Health/Heatinformation/

City of Phoenix Salvation Army: Heat Relief Response: 

The Salvation Army Emergency Disaster Heat Emergency 

Response

usw.salvationarmy.org

City of San Jose, California: Heat Wave Response sanjoseca.gov

City of Toronto: Hot Weather Response Plan toronto.ca/health/heatalerts/beatheat_program.htm

New York City Office of Emergency Management:

NYC Hazards: Extreme Heat nyc.gov/html/oem/html/hazards/heat.shtml

St. Louis, Missouri: Operation Weather Survival crh.noaa.gov/lsx/?n=ows

Washington, D.C: Heat program resources (homepage) dcema.dc.gov

U.S. EPA: Heat Island Effect epa.gov/heatislands
16 Climate Change and Extreme Heat Events

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