NOAA: July Temperature Below-Average for the U.S.
August 10, 2009
The July 2009 temperature for the contiguous United States was below the long-term average, based on records going back to 1895, according to a preliminary analysis by NOAA’s National Climatic Data Center in Asheville, N.C.
The average July temperature of 73.5 degrees F was 0.8 degrees F below the 20th century average. Precipitation across the contiguous United States in July averaged 2.90 inches, which is 0.14 inches above the 1901-2000 average.
U.S. Temperature Highlights
High resolution (Credit: NOAA)
- An abnormally strong, persistent upper-level pattern produced more than 400 record low minimum temperatures and 1,300 record low maximum temperatures (lowest high temperature) across the nine-state area that make up the Central region.
- Ohio, Iowa, Illinois, Indiana, West Virginia, and Pennsylvania experienced their coolest July on record. Kentucky, Missouri, Wisconsin, and Michigan each had their second coolest July on record, while Minnesota and Tennessee had their third coolest July on record.
- Death Valley, Calif., set a new monthly average maximum temperature at 121.3 degrees F. Temperatures in Death Valley reached 120 degrees F or higher for 22 days, beating the old record of 19 days.
- Several western locations recorded their all-time warmest July. Seattle-Tacoma Airport had an average July temperature of 69.5 degrees F, which was 4.2 degrees F above average. Seattle’s high temperature of 103 degrees F on July 29 is an all-time record. Alaska posted its second warmest July, Arizona had its third warmest, while New Mexico and Washington had their ninth warmest.
- Based on NOAA's Residential Energy Demand Temperature Index, the contiguous U.S. temperature-related energy demand was 13.3 percent below average in July. Much of this can be attributed to cooler-than-average conditions in the heavily-populated Northeast.
U.S. Precipitation Highlights
High resolution (Credit: NOAA)
- Precipitation was near normal for the contiguous U.S. as a whole. The Northeast saw its ninth-wettest July on record. Above-normal averages in the Northeast, Central and South were counter-balanced by below-normal averages in the Southeast, Southwest, the Wisconsin, Minnesota, Michigan and Iowa regions.
- Massachusetts and Rhode Island each recorded their second-wettest July on record, and Arkansas its third. Several states were much-above-normal, including Maine (fifth-wettest), and Vermont, New Hampshire, and Connecticut (each sixth-wettest).
- Moderate-to-exceptional drought covered 14 percent of the contiguous U.S., based on the U.S. Drought Monitor. This is one percentage point more than the end of June. Drought conditions worsened in southern Texas and northern Wisconsin, but remained largely unchanged in the West and along the western Canadian border.
- About 19 percent of the contiguous U.S. had moderate-to-extreme wet conditions at the end of July according to the Palmer Index, which measures both drought intensity and wet spell intensity.
Another Key Highlight
- July wildfire activity was below average, although the year-to-date number of wildfires remains above the 2000-2009 average. Last month, 8,515 new wildfires were reported and a total of about 1.7 million acres were burned, primarily in the West and Alaska, according to the National Interagency Coordination Center.
NCDC’s preliminary reports, which assess the current state of the climate, are released soon after the end of each month. These analyses are based on preliminary data that are subject to revision. Additional quality control is applied to the data when late reports are received several weeks after the end of the month and as increased scientific methods improve NCDC’s processing algorithms.
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