July Hottest Month on Record in Lower 48 States

July was the hottest month in the lower 48 states in records going back 117 years, capping the hottest 12 months ever in the continental U.S., the National Oceanic and Atmospheric Administration said.

The average temperature in the 48 states was 77.6 degrees Fahrenheit (25.3 Celsius), or 3.3 degrees above normal, NOAA said in a statement today. The old record was set in July 1936, John Ewald, a spokesman for the agency, said in an e-mail.

From August 2011 to July, the average temperature in the contiguous U.S. was 56.1 degrees, breaking the previous record set July 2011 to June by 0.07 of a degree, NOAA said. The first seven months of 2012 have also been the warmest start for any year in records going back to 1895.

“We have broken that 12-month record for four consecutive months going back to April,” said Jake Crouch, a climate scientist with the National Climactic Data Center in Asheville, North Carolina. That hasn’t happened before, he said.

Warmer temperatures in the winter helped pushed natural gas prices to a 10-year low in April, while heat since then has assisted futures in rebounding by more than 50 percent as people turn to air conditioning to keep cool.

Average precipitation in the contiguous U.S. was 0.19 inch below normal for a total of 2.57 inches in July, extending drought conditions to 62.9 percent of the region by the end of the month, according to the U.S. Drought Monitor.

Drought Markers

“The primary corn and soybean agriculture belt, hard hit by drought, experienced its eighth-driest July, third-driest June-July, and sixth-driest April-July growing season in the 1895-2012 record,” NOAA said.

The combination of drought and heat has caused 50 percent of U.S. corn to be rated poor to very poor, while 39 percent of soybeans have the lowest ratings, according to the Department of Agriculture. Corn futures have risen 59 percent since mid-June and soybeans have advanced 21 percent, potentially raising food prices, according to the United Nations.

The drought has helped contribute to warmer-than-normal temperatures, Crouch said by telephone.

“Whenever we have drought in the summer, daytime temperatures tend to increase,” he said.

No Predictions

Crouch said the current weather can’t be used to predict the next six months. If an El Nino ocean warming pattern develops in the central Pacific later this year, it could change the weather across the U.S., he said.

The U.S. Climate Prediction Center will update its forecast for an El Nino tomorrow, Crouch said. An El Nino often leads to more rain across the southern U.S.

“If an El Nino were to form, that would be a game-changer for us,” Crouch said.

The heat and lack of rain have also created “ideal wildfire conditions,” NOAA said. More than 2 million acres across the U.S. burned during July, nearly 500,000 more than the annual average and the fourth most since 2000.