From the NOAA National Climatic Data Center (NCDC), State of the Climate, National Overview, October 2009:
- The average October temperature of 50.8°F was 4.0°F below the 20th Century average and ranked as the 3rd coolest based on preliminary data.
- For the nation as a whole, it was the third coolest October on record. The month was marked by an active weather pattern that reinforced unseasonably cold air behind a series of cold fronts. Temperatures were below normal in eight of the nation’s nine climate regions, and of the nine, five were much below normal. Only the Southeast climate region had near normal temperatures for October.
- Statewide temperatures coincided with the regional values as all but six states had below normal temperatures. Oklahoma had its coolest October on record and ten other states had their top five coolest such months.
- Florida was the only state to have an above normal temperature average in October. It was the sixth consecutive month that the Florida’s temperature was above normal, resulting in the third warmest such period (May-October).
- The three-month period (August-October) was the coolest on record for three states: Nebraska, Kansas, and Oklahoma. Five other states had top five cool periods: Missouri (2nd), Iowa (3rd) , Arkansas (5th) , Illinois (5th) and South Dakota (5th) . Every climate division in Kansas (nine) and Nebraska (eight) recorded a record cool such period.
- For the year-to-date (January – October) period, the contiguous U.S. temperature ranked 43rd warmest. No state had a top or bottom ten temperature value for this period.
Precipitation Highlights – October
- The U.S. recorded its wettest October in the 115-year period of record. The nationwide precipitation of 4.15 inches was nearly double the long-term average of 2.11 inches.
- Regionally, two of the nation’s nine climate regions (the East North Central and South) saw their wettest October. The Central region had its second wettest October, while the West North Central had its fourth wettest. This was the first month since December 2007 that no region had below normal precipitation.
- Three states (Iowa, Arkansas, and Louisiana) saw their record wettest October. Fourteen other states had precipitation readings ranking in their top five category. Only three states (Florida, Utah, and Arizona) saw below normal precipitation.
- Arkansas continued its remarkable run of wetness in 2009. The state has seen four months with top three precipitation ranks this year (May, 1st wettest; July, 3rd wettest; September, 2nd wettest; October, 1st wettest). As a result, the state’s year-to-date average is the wettest in 115 years of record keeping. This contrasted with persistent dryness in Arizona, which saw its second-driest year-to-date period.
- The three-month (August-October) rainfall was record-setting for many adjacent divisions within Texas, Louisiana, Arkansas, Mississippi, Alabama, and Georgia. It is noteworthy that this occurred despite only one tropical cyclone (Claudette, in August) making landfall in the region during this period.
- By the end of October, moderate-to-exceptional drought covered 12 percent of the contiguous United States, the second-smallest drought footprint of the decade, based on the U.S. Drought Monitor. Major drought episodes in California and South Texas improved significantly. Drought conditions emerged across much of Arizona.
- About 45 percent of the contiguous United States had moderately-to-extremely wet conditions at the end of October, according to the Palmer Index (a well-known index that measures both drought intensity and wet spell intensity). This is the largest such footprint since February 2005.
Other Items of Note
- According to the NOAA Midwest Regional Climate Center in Champaign, Illinois, more than half of the long-term stations in the Midwest had one of their five wettest Octobers on record, with one out of five observing its wettest. Combined with the cold, this delayed crop planting and stunted crop maturity. Corn development was as much as four weeks behind in places, and the soybean harvest was well behind schedule throughout the region.
- Two major snow storms hit the contiguous United States during October. The first struck the Upper Midwest October 9th through 13th, while the second blanketed the western Plains States October 27th through 30th. By month’s end, 13.6 percent of the nation was under snow cover, according to NOAA’s National Operational Hydrologic Remote Sensing Center.
- Unusually cold and wet conditions across the middle of the country led to several snowfall records. Cheyenne, Wyoming observed 28 inches of snow during October, making this the city’s snowiest October on record. North Platte, Nebraska recorded 30.3 inches of snowfall, making October 2009 the snowiest month of all months on record for the city. The previous record was 27.8 inches, in March 1912.
- October, like September, saw below-normal fire activity in all respects. A total of 3,207 fires burned about 158,000 acres in October, according to the National Interagency Coordination Center. Each of these values is below this decade’s average for October.