The June average temperature for the contiguous U.S. was 70.4°F, 2.0°F above the 20th century average, and ranked as the 15th warmest such month on record.
Alaska was much warmer than average during June, with a statewide temperature 4.0°F above the 1971-2000 average and the third-warmest June in its 96-year period of record. A heat wave during the third week of the month brought temperatures in excess of 90°F to parts of the state, breaking daily record high temperatures at many locations.
The Ohio Valley and East Coast were much wetter than average. Eighteen states, from Georgia to Maine, had June precipitation totals that ranked among their 10 wettest. New Jersey and Delaware both had their wettest June on record. The New Jersey statewide precipitation total of 9.55 inches was 5.85 inches above average, and the Delaware precipitation total of 10.94 inches was 7.29 inches above average.
Below-average precipitation was observed across much of the West during June, which tends to be a dry month for the region. Arizona, Colorado, and Wyoming each had one of their 10 driest Junes on record. Utah was record dry with a statewide precipitation total of just 0.01 inch, 0.66 inch below average.
During June, approximately 4,000 wildfires charred more than 1.2 million acres, mostly across the western U.S. and Alaska. The number of fires was below average, while the acreage burned was above average. The Black Forest Fire, which burned more than 14,000 acres near Colorado Springs, Colo., destroyed more than 500 homes, and, according to preliminary assessments, is the most destructive wildfire in state history, in terms of property loss. The Yarnell Hill Fire, near Prescott, Ariz., destroyed more than 8,400 acres and was responsible for 19 firefighter fatalities.
Tropical Storm Andrea — the first tropical cyclone of the 2013 North Atlantic hurricane season — made landfall along Florida's Gulf Coast on June 6 with sustained winds of 65 miles per hour. The storm caused only minor damage as it moved through the Southeast, with the largest impacts being coastal flooding and weak tornadoes.
According to the July 2 U.S. Drought Monitor report, 44.1 percent of the contiguous U.S was experiencing drought conditions, the same size footprint as early June. Drought remained entrenched throughout much of the West and into the Central and Southern Plains, with the percent area of the nation experiencing severe (D2) to exceptional (D4) drought expanding from 28.5 percent to 33.0 percent. All locations east of the Mississippi River were drought free for the first time since May 2005.
The U.S. Climate Extremes Index (USCEI), an index that tracks the highest and lowest 10 percent of extremes in temperature, precipitation, tropical cyclones, and drought across the contiguous U.S., was 90 percent of average during June. Despite the below-average USCEI, extremes in warm daytime and warm night time temperatures and the spatial extent of the nation experiencing both wet and dry extremes were both above average.
On a local basis, over three times as many record warm highs and lows occurred than record cold highs and lows. Approximately 1,300 record warm daily high temperature records and 1,480 record warm daily low temperature records were tied or broken. In comparison, approximately 200 record cold daily low temperature records and 510 record cold daily high temperature records were tied or broken. (These numbers are preliminary and are expected to change as more data arrive.)
Oregon, Nevada, Idaho, and New Mexico each had January-June precipitation totals ranking among their 10 lowest. California had its driest first six months of the year with a precipitation total of 4.46 inches, 9.80 inches below average and 1.51 inches less than the previous record dry January-June of 1984.
Above-average precipitation was widespread across the eastern half of the country, with 12 states having one of their 10 wettest year-to-date periods. Illinois, Iowa, Michigan, and Wisconsin were all record wet for January-June.
The USCEI was 80 percent of average during January-June. Despite the below-average USCEI, extremes in the spatial extent of drought and 1-day precipitation totals were above average.
The REDTI value for the contiguous U.S. temperature-related energy demand during January-June was slightly below average.
