WASHINGTON - In 118 years of U.S. weather records, last month stands as king.
July was hotter than any month previously observed. The National Oceanic and Atmospheric Administration (NOAA) reported Wednesday that the July average temperature over the continental United States was 3.3 degrees warmer than the 20th-century average - and 0.2 degrees hotter than the previous record, set in July 1936.
Some of July's hottest temperatures occurred in the Plains, the Midwest and the Eastern Seaboard. Virginia had its hottest July on record, a full 4 degrees above average.
In 32 of the 48 contiguous states, July ranked among the top 10 hottest. At least 35 cities or towns had their hottest day on record for any day of the year.
The heat was intimately linked to a drought that expanded to nearly 63 percent of the Lower 48 in July. In a vicious cycle, high temperatures accelerated evaporation, which dried up the land surface, allowing for even more heat.
The worst of the drought centered in the Midwest and Plains. Nebraska, Iowa, Illinois and Missouri had July precipitation totals ranking among their 10 driest. NOAA said the area of the country in extreme to exceptional drought doubled from 10 percent in June to 22 percent in July. The drought reached the most extensive levels since December 1956.
The hot and dry conditions also stoked wildfires, which consumed more than 2 million acres in July, a half a million acres above average and the fourth-most on record since 2000.
Not only was July unrivaled for the heat it spread across the Lower 48, but so, too, were the past 12 months. Nationally, the past four 12-month periods have each successively established new records for the warmest period of that length.
In the 12-month span from August 2011 to July 2012, every state observed warmer-than-average temperatures except Washington, which was near average.
Chart-busting warmth has dominated 2012. The January to July average temperature in the continental United States was a record-smashing 4.3 degrees above normal, 1.1 degree above 1988, the next-warmest year on record.
Already this year across the Lower 48, more daily record high temperatures have been set or tied - with five months remaining - than in all of 2011. There have been almost 10 times as many record highs as record lows.
When considering connections to global warming and increasing concentrations of greenhouse gases worldwide, it's important to recognize the land area of the continental United States represents less than 2 percent of the globe and 2012 is just one year in a long history.
That said, global temperatures have also run warm. While NOAA's global report for July temperatures has not yet to be released, June ranked fourth-warmest on record globally and marked the 328th consecutive month of above average temperatures.
As global temperatures have been elevated for some time and long-term averages are rising, it's likely the same influences acting on global temperatures are also affecting temperatures on smaller scales.
In other words, increasing greenhouse gas concentrations are probably increasing the odds of these exceptionally warm years and months, wherever one resides.