The September 2009 average temperature for the contiguous United States was above the long-term average, according to NOAA’s monthly State of the Climate report. Based on records going back to 1895, the monthly National Climatic Data Center analysis is part of the suite of climate services NOAA provides.
|September temperature rankings. Source: NOAA. Click to enlarge.|
The average September temperature of 66.4 °F (19.1 °C) was 1.0 °F (0.56 °C) above the 20th Century average. Precipitation across the contiguous United States in September averaged 2.48 inches (63 mm), exactly the 1901-2000 average.
Below-normal temperatures across parts of the south and Northeast were offset by record high values in the West and above normal temperatures in the Northwest and northern tier states resulting in a higher average temperature for the contiguous United States.
Both California and Nevada experienced their warmest September of the 115-year record. Additionally California, Nevada, Montana and North Dakota posted their third warmest, Idaho its fourth warmest, Utah fifth warmest, Minnesota sixth warmest, and Oregon registered its eighth warmest.
On a regional level, the West experienced its warmest September on record. The Northwest and West North Central experienced their sixth and eleventh warmest such periods. Below-normal temperatures were recorded in the South and Northeast.
While precipitation equaled the long-term average for the contiguous US, regional amounts varied widely. The South experienced its sixth-wettest September, which was countered by the sixth-driest period around the Great Lakes and upper Midwest region.
Arkansas registered its second wettest September, Tennessee its fifth, with Mississippi and Alabama posting their sixth wettest on record. Despite notable and flood-producing rains in northern Georgia, drier conditions near the coast kept the state’s overall average out of the top ten.
Maine and Wisconsin each experienced their fourth driest September and both New Hampshire and Michigan had their seventh driest such periods.
By the end of September, moderate-to-exceptional drought covered 15% of the contiguous United States, based on the US Drought Monitor. Drought intensified in the Upper Midwest and eastern Carolinas, while remaining entrenched in much of the West. Drought conditions remain severe in south Texas, despite some improvement.
During September, 5,535 fires burned approximately 378,523 acres—both were below the 2000-2009 average for the month. The acreage burned by wildfires was roughly half of the 2000-2009 average. For the January-September period, 70,217 fires were reported, which is slightly above the 10-year average, while acreage burned is slightly less than average.