La Niña Impacts 

and Outlook

Midwest Region

November 2021

Typical La Niña Winter Pattern

Highlights for the Midwest

A La Niña develops when sea surface 

temperatures are cooler-than-average 

in the eastern equatorial Pacific for an 

extended time. This is important to North 

America because La Niña can impact our 

weather patterns, especially in late winter 

and early spring. 

While no two La Niña events are alike, there 

are some general tendencies that emerge. 

For instance, the polar jet stream is typically 

farther south than usual. 

This pattern brings enhanced chances for 

below-normal temperatures to the upper 

Midwest, particularly in the more western 

areas. The Ohio River Valley also sees 

enhanced chances of wetter-than-normal 

conditions, particularly for late winter. 

Warmer or drier weather events can still 

occur, but those events may be milder and 

less frequent across the region.

As shown by the thick blue arrow in the above graphic, a typical storm 

path during La Niña tends to track across the northwestern U.S. and dive 

just south of the Great Lakes. This generally means increased chances of 

precipitation for the Northwest, portions of the Great lakes, and the Ohio 

River Valley, with occasional cold air outbreaks across the north.

Image courtesy of the National Oceanic and Atmospheric Administration.

La Niña Outlook

Winter Temperature and Precipitation Outlooks

Valid for December 2021 - February 2022

Temperature Precipitation

The winter temperature outlook (issued in October) indicates that the 

majority of the Midwest has slightly increased chances of above-normal 

temperatures, with higher probabilities in the southeast portion of the 

region. The extreme northwest portion of the region has equal chances of 

above-, below-, and near-normal temperatures.

The winter precipitation outlook shows a 

slightly increased chance of above-normal 

precipitation for most of the Midwest, with 

higher probabilities over the Great Lakes 

region. There are equal chances of above-, 

below-, and near-normal precipitation for 

most of Minnesota and Iowa along with 

small portions of western Wisconsin and 

northwest Missouri.

A La Niña Advisory is currently in effect, 

which means La Niña conditions have 

developed and are expected to continue.

Forecasts indicate this La Niña will 

strengthen, peaking as a moderately 

strong event in late fall or early winter. 

According to the NOAA Climate Prediction 

Center, there is an 87% chance that these 

conditions will last through the winter 

and about a 63% chance that La Niña will 

continue into the early spring. 

Images courtesy of the National Oceanic and 

Atmospheric Administration.

Midwest Region La Niña Impacts and Outlook | November 2021 

https://www.drought.gov/drought/resources/reports

Contact: Doug Kluck (doug.kluck@noaa.gov)

Melissa Widhalm (mwidhalm@purdue.edu)
Potential Winter and Spring Impacts

The image above shows areas that tend to receive more (blue) or less

(tan) than average snowfall during a La Niña year. The upper Midwest

and Great Lakes tend to have above-average snowfall during La Niña 

years while the lower Midwest is usually near-average.

Economy

Negative impacts commonly associated with La Niña are increases in 

heating costs, snow removal, and difficulties in transportation. Colder

and snowier weather may also hamper construction. Sectors that 

depend on winter weather (recreation, snow removal companies, and

road salt sales) could see a benefit from increased snowfall.

Agriculture

Most La Niña impacts are felt outside the 

growing season. However, increased snowpack 

could insulate crops from harsh conditions, and 

colder temperatures in the upper Midwest could 

limit certain pests and diseases. Cold outbreaks 

can adversely impact livestock producers due to 

increased operating costs and animal stress. Also, 

with much of the lower Midwest entering winter 

with abundant soil moisture, wetter-than-normal 

winter conditions could result in delayed spring 

planting. 

Ecosystems and Rivers

Periods of wintry weather can both benefit and 

harm native species, some of which thrive/

depend on typical cold winter periods. Water 

availability is complex and depends on both the 

rain/snow mix and when the precipitation falls. 

Winter precipitation on unfrozen soils would 

be beneficial to recharge streams in the upper 

Midwest suffering from drought, while a large 

snowpack on frozen soils could lead to increased 

runoff and higher river levels in spring, depending 

on how spring weather develops.

Comparisons and Limitations

Winter Conditions During Past La Niña Years

The maps to the left show late winter (Jan.-Feb.-

Mar.) conditions during the last La Niña event in 

2020-21. Much of the region had near-normal 

temperatures (top), with the upper Midwest 

above-normal (orange) and pockets of belownormal (green) in central and southwest areas. 

Precipitation (bottom) was above-normal (green) 

in the lower Midwest and below-normal (yellow) 

across the Great Lakes. As shown by last year's 

unexpected pattern, it should be noted that 

each La Niña is different and other factors may 

influence the overall winter. La Niña impacts can 

be limited by many factors, including long-term 

trend and being overcome by short-term weather 

events.

While past La Niña events can help inform 

forecasters about certain conditions, there are 

limitations. For instance, in the Midwest, La Niña 

is not known to impact: 

• first freeze in the fall (early or late) 

• last freeze in the spring (early or late)

• potential for ice storms or blizzards

• track/intensity of any one weather system

• potential for drought/flooding in the spring.

JFM 2021

Temperature Departure

JFM 2021

Precipitation Percentage

Maps courtesy of MRCC

Midwest Partners

Midwestern Regional Climate Center 

(MRCC) 

mrcc.purdue.edu

American Association of State 

Climatologists

www.stateclimate.org

National Integrated Drought Information 

System 

www.drought.gov

USDA Midwest Climate Hub

www.climatehubs.usda.gov/hubs/midwest

National Oceanic and Atmospheric 

Administration 

www.noaa.gov

 Great Lakes Environmental Research 

 Laboratory

 www.glerl.noaa.gov

 National Centers for Environmental

 Information 

 www.ncei.noaa.gov

 NWS Climate Prediction Center

 www.cpc.ncep.noaa.gov

 NWS Central Region Headquarters 

 www.weather.gov/crh

 North Central River Forecast Center 

 www.weather.gov/ncrfc

 Ohio River Forecast Center 

 www.weather.gov/ohrfc

Midwest Region La Niña Impacts and Outlook | November 2021 

https://www.drought.gov/drought/resources/reports

Contact: Doug Kluck (doug.kluck@noaa.gov)

Melissa Widhalm (mwidhalm@purdue.edu)