Over 100 High Temperature Records Per Day in July Outnumber Cold Records by 17 to 1

The 3,135 new daily high temperature records in July 2012, over 100 per day, exceeded cold records by a factor of 16.6 to 1. The heat record count was the highest since the phenomenal 6,182 in March. For the summer to date (June-July), the ratio is now 7.9 to 1. For 2012 overall, the ratio of 11.8 to 1 is over 4 times the value for 2011.

The heat record count is a little less than half of the 6,788 records set in the record hottest month of July 1936, which is actually quite impressive given the additional 76 years of data since then. Furthermore, this July's ratio is 23% higher than the 13.5 in 1936.

Image (click to enlarge):
- Monthly ratio of daily high temperature to low temperature records set in the U.S. for July 2011 through July 2012, seasonal ratio for summer and fall 2011, winter, spring and summer 2012 to date, and annual ratio for 2012 and 2011.
CapitalClimate chart from NOAA/NCDC data, background image © Kevin Ambrose (www.weatherbook.com). 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.

Preliminary Analysis Continues to Show Trend to Hottest Month in US History

Image (click to enlarge): Hottest U.S. average monthly temperatures (all July) and 2012 average through July 28; CapitalClimate chart from NOAA/NCDC data

Aug. 7 Update: Preliminary unadjusted data from NCDC show the July average at 77.3°, which is 0.1° below the record.

Original post:
The preliminary weekly temperature analysis, posted this morning by the National Climatic Data Center (NCDC), continues to show July 2012 as the hottest month in U.S. history. The national average temperature for the week ending July 28 increased to 77.6°, which is 3° above the climatological normal. The month-to-date average of 77.5° is 0.1° above the all-time hottest month of July 1936.

Indianapolis Smashes 1936 Record for Warmest Month in History, Most 90° and 95° Days

With a high of 91° as of 2 pm today, Indianapolis is virtually certain to break its all-time record highest average temperature for a month. The National Weather Service reports:

July 2012 will go down in history as the warmest month of record at Indianapolis. The average temperature for July will remain near 84 degrees...eclipsing the previous record of 82.8 degrees set in July 1936 by nearly one degree. The average monthly temperature was 84.1 degrees through the first 29 days.

The temperature will exceed 90 degrees on both Monday and Tuesday at the Indianapolis International Airport. The number of 90-degree days for the month will climb to 28 ... besting the old record of July 1901 by 3 days. At the end of July the total number of 90-degrees for the year will be 43...the most for a year since 1988. The record is 58 days set in 1983.

July's record for the most 95-degree days in a month is expected to climb to 19 on Tuesday. The previous record of 16 was set in July 1936. The total number for the year will increase to 22 days ... trailing only 1936 with 31 and 1988 with 23.

The number of 100-degrees days for the month will likely remain at 7...second only to July 1936 which had 9 days. The yearly total will also remain at 9 days...trailing only 1936 with 12 and 1934 with 10. The current forecasts do not indicate any 100 degree temperatures for the Indianapolis area. The latest 100-degree reading for the Indianapolis area occurred on September 15, 1939.

National Climatic Data Center records show that Indianapolis climate history began in 1871:

Station Thread for Indianapolis Area, IN
   Name                           Period in Thread  
1  INDIANAPOLIS INTL AP           01/1943 to 12/2011 
2  INDIANAPOLIS WB CITY           09/1896 to 12/1942 
3  INDIANAPOLIS (supplied by NWS) 02/1871 to 08/1896  

33rd Consecutive Warm Week Confirms July Trend to Hottest Month in US History

As posted last week, preliminary reports indicate that July 2012 is likely to be the hottest month since U.S. national temperature records began in 1895. With just 3 days left to go, CapitalClimate analysis of National Weather Service reports from 215 stations across the 48 contiguous states shows that the unadjusted U.S. national average temperature was 3.4° above climatological normal for the week ending yesterday, July 28, down slightly from 3.6° last week. This was up, however, from the National Climatic Data Center (NCDC) adjusted result of 3.2° in the previous week.

Once again, the month-to-date averages show that nearly every part of the country was warmer than average, with California and the immediate coast of the Pacific Northwest being the notable exceptions. Of the 215 locations, 85% were above average, and all of the 9 NCDC climate regions have been warmer than average for each of the 3 weeks through July 21. (NCDC data through the 28th will be reported on Tuesday.)

Images (click to enlarge):
- Weekly average U.S. temperature departures from normal, weeks ending June 4, 2011 (20110604) through July 28, 2012 (20120728); CapitalClimate chart from NOAA/NCDC data
- Weekly average NWS station temperature departures from normal, week ending July 28, 2012; stations listed alphabetically by state and 3-character station identifier; CapitalClimate chart from NWS data
- Average U.S. temperature departure from normal for July 1-28, 2012 from High Plains Regional Climate Center