July 2012 has finished as the hottest month in the contiguous US since national records started in 1895
, according to recent figures from the National Climatic Data Center
. The national monthly average of 77.6F in July 2012 was 0.2F warmer than the previous hottest month of July 1936, set during the great Dust Bowl era. The month was dominated by hot and dry conditions over most of the US, with the heat mainly centered over the Great Plains through the midwest and Ohio Valley into the mid Atlantic seaboard
. Seven states recorded their 2nd warmest July on record on a statewide average.
The record hot month extended the persistent warmth that began last summer, with the last 12 months now standing as the warmest 12 month period in the US since 1895
. The average US national temperature over the last 12 months has been 56.1F (13C), or about 3.3F above normal. Previous to this year, the warmest 12 month period was Nov 1999 to Oct 2000 which averaged 2.7F above normal at 55.5F. The record warmth has also been occurring north of the border as well. Winnipeg has recorded 13 consecutive months above normal dating back to July 2011, and the last 12 months (August 2011-July 2012) have been the warmest 12 month period on record since records began in Winnipeg in 1872
. Prior to this year, the warmest 12 month period in the city was from Nov 1877 to Oct 1878, thanks to the record warm El Nino winter of 1877-1878 (still the warmest winter on record in Winnipeg)
|Graph of national US temperature |
anomalies since 1895. Note how much
warmer 2012 has been to date, warmer
than any other similar period since 1895.
In addition, the year to date average of 56.4F so far in 2012 is the warmest Jan-July period ever recorded in the US
, easily beating the previous warmest Jan-July period of 1998 (at 54.5F) The graph left shows how dramatically warmer this year has been to date, especially with the warm winter and spring that has made this year warmer than any other corresponding period in US history (since 1895 anyways) In Winnipeg, our year to date average through the end of July 2012 is 4.0C
, tying 1987
for the warmest year through July. (1987 stands as Winnipeg's warmest calendar year with an average of 5.4C.) For more details on the exceptional warmth of July 2012 and the past year, see blog entries from Dr Jeff Masters
and climate historian Chris Burt