State of the Climate
National Overview
September 2004

September:

• September temperatures were warmer than average for the contiguous nation, with the East North Central region having significantly warmer than average temperatures. Alaska was cooler than average. For information on temperature records during the month, please go to NCDC's Extremes page.
  
  
• The precipitation signal was mixed with wetter than average conditions across much of the east coast mostly as a result of tropical systems and less than average precipitation in a band from Michigan and Wisconsin, south to Louisiana. The northern Great Plains were also wetter than average for the month. For more information on drought during September, please visit the U.S. Drought page.
  
  
• Indices used to determine the state of ENSO suggest that the Equatorial Pacific was in a weak warm phase (El Nino), with Sea Surface Temperatures continuing above normal across the central equatorial Pacific during September. To see the latest NOAA advisory and typical impacts of a La Nina or El Nino episode for the U.S., go to NOAA's Climate Prediction Center.

National:

• September 2004 ranked as the 28th warmest September in the 1895 to present record. The preliminary nationally averaged temperature was 66.5°F (19.2°C), which was 1.0°F (0.6°C) above the long-term mean.
• September 2004 had above average precipitation, nationally, ranking 13th wettest.
  
  For tables of national, regional, and statewide data from 1895-present, for September, last 3 months or other periods, please go to the Climate At A Glance page.
  
  
• July-September temperature was below average and ranked as the 28th coolest such period in the 1895 to present record. The preliminary nationally averaged temperature for July-September was 70.4°F (21.3°C) which was 0.5°F (0.3°C) below the long-term mean.
• July-September had above average precipitation, ranking 14th wettest in the last 110 years.
  
  
• The October 2003-September 2004 temperature was above average and ranked as the 19th warmest such period in the 1895 to present record. The preliminary nationally averaged temperature was 53.5°F (11.9°C) which was 0.7°F (0.4°C) above the long-term mean.
• Precipitation was above average for October-September, ranking 29th wettest for the last 12 months based on a record of 109 such periods.
  
  Regional and Statewide:
  
  
• September 2004 temperatures ranked much above average for 7 states, including Minnesota and Wisconsin, which had their 4th warmest September on record. A further 21 states had above average temperature.
• Alaska temperatures were cooler than average for September with an anomaly of -3.4°F (-1.9°C), following a record warm May, June, July and August for the state.
• September was much wetter than average for 14 states, including Pennsylvania, West Virginia and Georgia, which had their wettest September on record.
• The 3 month period, July-September, was cooler than average for 19 states and much warmer than average for 3 states. A further 7 states were warmer than average for July-September 2004.
• July-September 2004 was much wetter than average for most of the east, with New York and Pennsylvania having their wettest July-September on record. Eight states were drier than average including Louisiana, which had its fifth driest such period since 1895.
• The last 12 months were much warmer than average for 6 western states. Much of the rest of the nation had near average to above average temperatures.
• The last 12 months were record wet for Pennsylvania, with New York having its second wettest October-September. Dry conditions prevailed across parts of the Southwest and High Plains.

  See NCDC's Monthly Extremes web-page for weather and climate records for the month of September.