Phoenix Nears Record of Most 110 Degrees Days

Of all the places in the US, Phoenix is perhaps showing the greatest results of the heat island effect and rising temperatures, largely due to global warming and climate change.


PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE
PHOENIX AZ 855 AM MST WED AUG 22 2007

...2007 COULD SET RECORD FOR MOST 110+ DEGREE DAYS AT PHOENIX...

THROUGH AUGUST 21ST...THERE HAVE BEEN 27 DAYS WITH A HIGH TEMPERATURE OF 110 DEGREES OR GREATER AT PHOENIX SKY HARBOR INTERNATIONAL AIRPORT.

THIS TIES 1989...1985...1974 AND 1936 AS THE 3RD MOST ON RECORD. THE MOST ON RECORD IS 28...WHICH OCCURRED IN 2002 AND 1979

/SEE TABLE 1 BELOW FOR ADDITIONAL INFORMATION/.

HOWEVER...SUMMER 2007 IS FAR FROM OVER. THE LATEST OBSERVED 110 DEGREE OR GREATER TEMPERATURE OCCURRED ON SEPTEMBER 15TH /IN 2000/...MEANING THERE IS NEARLY A MONTH-LONG WINDOW REMAINING WHEN 110+ TEMPERATURES ARE CLIMATOLOGICALLY POSSIBLE.

WITH HIGH TEMPERATURES FORECAST TO REMAIN NEAR 110 DEGREES THROUGH THE END OF THIS WEEK...THERE IS A HIGH PROBABILITY THAT 2007 WILL SET THE NEW RECORD.

HAVE 110+ DEGREE DAYS BEEN INCREASING OVER THE YEARS?

YES...BASED ON OBSERVED MAXIMUM TEMPERATURES FOR PHOENIX FROM 1896 THROUGH 2007

/SEE TABLE 2 BELOW FOR ADDITIONAL INFORMATION/.

POSSIBLE REASONS FOR THIS TREND INCLUDE URBANIZATION AND REGIONAL/GLOBAL CLIMATE CHANGE.

&& TABLE 1 - TOP 10 YEARS WITH HIGHS OF 110 OR GREATER AT PHOENIX

RANK YEAR MAY JUN JUL AUG SEP TOT
1) 2002 0 12 9 6 1 28
1979 0 10 13 2 3 28
3 ) 2007 0 10 12 5* - 27*
1989 1 9 16# 1 0 27
1985 0 10 10 7 0 27
1974 1 18# 6 1 1 27
1936 0 13 13 1 0 27
8) 2003 1 2 15 6 2 26
9 ) 1995 0 2 11 11# 1 25
1981 0 11 6 8 0 25
* THROUGH AUG 21 2007
# INDICATES ALL-TIME MONTHLY RECORD

TABLE 2 - ANNUAL FREQUENCY OF 110+ DEGREE DAYS BY DECADE

1890S 5.3 PER YEAR
1900S 5.2 PER YEAR
1910S 3.8 PER YEAR
1920S 7.7 PER YEAR
1930S 11.8 PER YEAR
1940S 7.2 PER YEAR
1950S 6.7 PER YEAR
1960S 10.3 PER YEAR
1970S 17.0 PER YEAR
1980S 19.0 PER YEAR
1990S 13.6 PER YEAR
2000S 21.9 PER YEAR*
* THROUGH AUG 21 2007

ADDITIONAL GRAPHICS ARE AVAILABLE ON OUR WEBSITE... WWW.WEATHER.GOV/PHOENIX.