NOAA: July 2012 was the hottest month on record in the contiguous U.S.

Posted at 5:03 AM, Aug 09, 2012

RICHMOND, Va. (WTVR) - We already know that July 2012 was a record hot month for Richmond. CLICK HERE to read about our second-hottest July on record at Richmond International Airport. Virginia had its hottest July on record.

Virginia is the only state in the contiguous U.S. to have a record hottest July this year. But, as you can see, many other states had near-record hot Julys.

For the contiguous United States, July 2012 was not only the hottest July on record, it was also our hottest month ever recorded, since record-keeping began in 1895, according to NOAA Climate Services (data provided by NOAA's National Climatic Data Center). NOAA’s National Climatic Data Center (NCDC) data concludes the average temperature for the contiguous United States (i.e., not including Alaska and Hawaii) during July was 77.6°F, which is 3.3°F warmer than the 20th-century average. Granted, July is typically our warmest month of the year, including for Richmond, so it isn't a surprise that our hottest month out of all 12 possible in a year would come from a July. This July makes sense as well considering the broad, stubborn, extreme heat ridge that remained parked over the central U.S. nearly the entire month, at times extending its fingers farther east to the Eastern U.S., producing Virginia's periodic heat waves and triple-digit temperatures during July 2012. The NCDC says, "32 states had July temperatures among their ten warmest."

IMAGE: NOAA Climate Services

July 2012 Average Temperatures across U.S.
IMAGE: NOAA Climate Services

What is perhaps more helpful for you to visualize how much hotter this July was is the departure from normal temperature map for July 2012.  When we make the following comparisons for departures from average, we are looking at the new 1981–2010 average data set released last year by the NCDC. The NCDC says about the map below, "Shades of red indicate temperatures up to 8° Fahrenheit warmer than average, and shades of blue indicate temperatures up to 2° Fahrenheit cooler than average—the darker the color, the larger the temperature difference."

IMAGE: NOAA Climate Services

July 2012 Departure from Average Temperature.
IMAGE: NOAA Climate Services

July also continues our year-to-date trend of being the hottest first half of a year on record. NCDC states in their July 2012 report, "With warmer-than-average conditions in place since March, 2012 continues to be warmest year-to-date period on record. As July came to a close, a new record was set, breaking the one set just last month: the past 12-month period has been the warmest the nation has experienced since record-keeping began in 1895."

In addition, this continues our trend of the hottest last year (12-month scale) on record. The NCDC concludes, "The August 2011-July 2012 period was the warmest 12-month period of any 12-months on record for the contiguous U.S., narrowly surpassing the record broken last month for the July 2011-June 2012 period by 0.07°F. The nationally averaged temperature of 56.1°F was 3.3°F above the long term average. Except Washington, which was near average, every state across the contiguous U.S. had warmer than average temperatures for the period."

With dry and hot conditions, wildfires were a big problem in July, and continue to burn in some states into August. The NCDC report states, "over two million acres burned nationwide during July due to wildfires, the fourth most on record since 2000."

As we've also already reported, the U.S. drought overall continues the status quo, with some areas improving, while others worsen, and no significant improvement widespread. The NCDC report concludes the extreme July heat exacerbated the ongoing drought. "According to the U.S. Drought Monitor (USDM), at the end of July, 62.9 percent of the contiguous U.S. was experiencing moderate to exceptional drought. This is an increase of about 7 percent since the end of June. The maximum value of 63.9 percent of the country in moderate or extreme drought reached on July 24 is a record in the 13-year history of the Drought Monitor."

For the full NCDC July 2012 report, CLICK HERE.

Meteorologist Carrie Rose
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