# Presentation: 908102

## Brian McInerneyHydrologistNational Weather ServiceSummer of 2007 Climate Overview

## Climate Overview

- This quick study analyzes the past summer months’ average temperature for Salt Lake City, and compares it to the long term record.  What we’ve found is that this past summer (June through August) was the warmest on record.  Additionally, the month of July 2007 was the warmest July, and also the warmest month ever recorded.  Following July, the month of August 2007 was the second warmest August on record.
- We determine the mean monthly temperature by recording the high and low temperature for the day, divide by two, and come up with a daily average.  We do this for the entire month, and come up with a monthly temperature average. Records used in the analysis date back to 1874.
- When we look at this past summers’ temperatures, we compare the levels with what we call normal.  Normals are determined by analyzing data for the past 30 years and come up with an average.  The time frame currently used is from 1971 to 2000.  In essence, we’ve compared this past summer with the past 30 summers dating back to 1971. The normal average shifts every 10 years.  For example, when we reach 2010, the average will then shift from 1981 to 2010.
- Additionally, a short section on the summers precipitation was viewed.  While summertime precipitation is not figured into the State’s water supply equations, it is interesting to note that Utah received a very insignificant amount of precipitation compared to Texas, which dealt with record flooding during the summer months. Texas also recorded the coldest average July, while Utah had the hottest. I included this small section to illustrate the stagnant high pressure pattern which persisted over our region for the summer months, and the low pressure that dominated the great plains region.

## Climate Overview

- Days Where Temperature Reached 90 Degrees or Higher

## Salt Lake City June 2007Days Where Temperatures Reached 90 Degrees or Higher 

- 2007 - 16 Days

- Record Year 1961 – 20 Days

## Salt Lake City July 2007Days Where Temperatures Reached 90 Degrees or Higher

- 2007 - 29 Days

- Record Year 1960 – 31 Days

## Salt Lake City August 2007Days Where Temperatures Reached 90 Degrees or Higher

- Salt Lake City August 2007Days Where Temperatures Reached 90 Degrees or Higher

- Record Year 1967 – 31 Days

- 2007 - 22 Days

## Salt Lake City Summer 2007Total Days Where Temperatures Reached 90 Degrees or Higher

- Salt Lake City Summer 2007Total Days Where Temperatures Reached 90 Degrees or Higher

- Record Years – 82 Days

- 2007 - 67 Days

## Climate Overview

- Days Where Temperature Reached 95 Degrees or Higher

## Salt Lake City June 2007Days Where Temperatures Reached 95 Degrees or Higher

- Salt Lake City June 2007Days Where Temperatures Reached 95 Degrees or Higher

- 2007 - 8 Days

- Record Year 1961 – 16 Days

## Salt Lake City July 2007Days Where Temperatures 95 Degrees or Higher

- Salt Lake City July 2007Days Where Temperatures 95 Degrees or Higher

- 2007 – New Record 24 Days

- Old Record Year 1960 – 23 Days

## Salt Lake City August  2007Days Where Temperatures Reached 95 Degrees or Higher

- Salt Lake City August  2007Days Where Temperatures Reached 95 Degrees or Higher

- Record Year 1967 – 22 Days

- 2007 - 15 Days

## Salt Lake City Summer 2007Total Days Where Temperatures Reached 95 Degrees or Higher

- Salt Lake City Summer 2007Total Days Where Temperatures Reached 95 Degrees or Higher

- Record Years – 61 Days

- 2007 - 47 Days

## Climate Overview

- Days Where Temperature Reached 100 Degrees or Higher

## Salt Lake City June 2007Days Where Temperatures 100 Degrees or Higher

- Salt Lake City June 2007Days Where Temperatures 100 Degrees or Higher

- 2007 - 2 Days

- Record Year 1961 – 8 Days

## Salt Lake City July 2007Days Where Temperatures Reached 100 Degrees or Higher

- Salt Lake City July 2007Days Where Temperatures Reached 100 Degrees or Higher

- 2007 – 11 Days

- Record Year 1960 – 15 Days

## Salt Lake City August 2007Days Where Temperatures Reached 100 Degrees or Higher

- Salt Lake City August 2007Days Where Temperatures Reached 100 Degrees or Higher

- Record Year 1994 – 7 Days

- 2007 - 4 Days

## Salt Lake City Summer 2007Total Days Where Temperatures Reached 100 Degrees or Higher

- Salt Lake City Summer 2007Total Days Where Temperatures Reached 100 Degrees or Higher

- Record Years – 30 Days

- 2007 - 17 Days

## Climate Overview

- Salt Lake City Temperature Extremes

## Hottest Summer on RecordHighest Average June - August Temperatures on RecordSalt Lake City

- 2007		79.3 deg. F
- 1994		78.6 deg. F
- 2003		78.2 deg. F
- 1988		77.7 deg. F
- 2006		77.6 deg. F
- 1961		77.5 deg. F
- 2000		77.3 deg. F
- 1996		77.2 deg. F

- Average 73.9 deg. F

## Warm JuneHighest Average Monthly Temperatures on RecordSalt Lake City

- June 1988		75.7 deg. F
- June 1961		74.7 deg. F
- June 1994		74.3 deg. F
- June 1986		73.5 deg. F
- June 1996		73.4 deg. F
- June 2007		73.2 deg. F
- June 2006		73.2 deg. F

- Average 69 deg. F

## Record Hot July Highest Average Monthly Temperatures on RecordSalt Lake City

- July 2007		84.0 deg. F
- July 2003		83.4 deg. F
- July 2006		83.1 deg. F
- July 2002		81.9 deg. F
- July 1960		81.2 deg. F

- Average 77 deg. F

## Near Record Hot August Highest Average Monthly Temperatures on RecordSalt Lake City

- Aug 1994		80.8 deg. F
- Aug 2007		80.7 deg. F
- Aug 2003		80.0 deg. F
- Aug 2001		79.0 deg. F
- Aug 2000		78.9 deg. F

- Average 75.6 deg. F

## Climate Overview

- Precipitation

## 90 Day (May through July 2007) Observed Precipitation

## This past summer was the hottest on record.  Was this due to climate change?
Anecdotally, the warm summer is on track with what we would see with climate change. Climate models call for continued warming.  We broke many high temperature records this summer, and on face value this is the type of warming we would experience with climate change.
As temperatures across the west continue to warm, the warming we recorded this past summer may be caused by climate change, but at this point in time, we do not have enough data to quantitatively and statistically say that this warming was caused by climate change.  If we continue to warm, and forecasts indicate that that is the case, then at some point we will have enough data to definitively say that it is caused by climate change.  Until that time, we shall look at the data in a more qualified manner. 

- Anecdotally, the warm summer is on track with what we would see with climate change. Climate models call for continued warming.  We broke many high temperature records this summer, and on face value this is the type of warming we would experience with climate change.
- As temperatures across the west continue to warm, the warming we recorded this past summer may be caused by climate change, but at this point in time, we do not have enough data to quantitatively and statistically say that this warming was caused by climate change.  If we continue to warm, and forecasts indicate that that is the case, then at some point we will have enough data to definitively say that it is caused by climate change.  Until that time, we shall look at the data in a more qualified manner.

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## Contact Information

- This presentation can be found at:
- _http://www.wrh.noaa.gov/Saltlake/river/presentations_
- Additional Information
- Contact
- Brian McInerney
- Hydrologist
- National Weather Service
- 801-971-2033 c
- brian.mcinerney@noaa.gov