Thursday, September 1, 2011

U.S. Heat Records Continue Crushing Cold: Incredible 22 to 1 Ratio in August

When new daily high temperature records overwhelmed low temperature records by well over 20 to 1 in the first 9 days of August, it was impressive enough, but the amazing excess has continued right through the end of the month. The over 3000 daily heat records swamped the 142 cold records by 22.2 to 1. In fact, the excess of heat records over 3000 was more than the total number of cold records!

For meteorological summer (June-August) as a whole, the ratio increased to 11.4 to 1 from 8.4 to 1 through July, and the year to date is now at 3.4 to 1, more than 50% above the average for the previous decade.

Texas accounts for 1343 of the heat records in August, but Oklahoma, Arkansas, Missouri, and Kansas are also well represented. Despite the moderating maritime influence of the Gulf of Mexico, the 95° at Key West Naval Air Station (KNQX), Florida on the 5th, 10th, and 13th set new records for each date and also tied the all-time highest temperature. In all, Key West set or tied temperature records on 12 days out of the month.

The 47 new and 53 tied all-time high temperature records were focused mainly in the first week of the month, but Texas made a strong showing in the final few days, with Ft. Hood breaking its old record of 108° for the second time at 112° on the 27th and then tying it the next day. Houston (109°) and Austin (112°) also tied all-time records.

Preliminary data from ESRL/NOAA through August 30 show that temperatures over the entire contiguous U.S. and adjacent Canada were above or within less than 0.5°C of the 1981-2010 average with the exception of immediate coastal California and Washington.

Images (click to enlarge):
- Monthly ratios of daily high temperature to low temperature records set in the U.S. for July 2010 through August 2011. Data from NOAA National Climatic Data Center, background image © Kevin Ambrose ( Includes historical daily observations archived in NCDC's Cooperative Summary of the Day data set and preliminary reports from Cooperative Observers and First Order National Weather Service stations. All stations have a Period of Record of at least 30 years.
- Decadal average ratios of heat records to cold records, from University Corporation for Atmospheric Research
- Preliminary August 2011 U.S. temperature departure from 1981-2010 average from ESRL/NOAA

1 comment:

Tim said...

Although it makes virtually no difference these days, I have a nit to pick regarding the vertical scales you use in your "Ratio of Heat to Cold Records" plots. In order to treat time intervals where cold records outnumber heat records (a rarity now, I know), your scale be reciprocal below 1 (or, it should be linear in "Cold over hot". In other words, the 0.7 bar in December, 2010 should go below 1.0 as far as 1.43 (= 1/0.7) goes above 1.0.

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