Preliminary
Wyoming Monthly Climatology
September 2004

Statewide Summary

During the month of September, temperatures were within +/- 2°F of normal with the extreme western region of Wyoming having generally the coldest readings. Precipitation was general well above normal over the southern half of the state with below normal amounts over Park and Campbell counties. During this year's growing season (1 April - 30 September), above normal precipitation extended from Albany County to Yellowstone National Park, with below normal amounts to the NE and SW of this band. Areas especially from eastern Park County to Niobrara County were serverely dry. This precipitation pattern has also been persistent for the 2004 water year (1 October 2003 to 30 September 2004).

Weather Summary: For the week ending Friday, September 3, temperatures were highly variable throughout the State. Temperatures ranged from 4.1 degrees below normal in Worland to 2.6 degrees above normal in Kaycee. The highest temperature was 97 degrees in Sheridan, while the lowest temperature was 29 degrees in Big Piney. A trace or more of precipitation was reported in most areas, but nearly all was below normal. The most precipitation fell in Recluse with 1.50 inches and 0.83 in Afton.

Weather Summary: For the week ending Friday, September 10, temperatures were mostly below normal. Temperatures ranged from 3.4 degrees below normal in Recluse to 1.7 degrees above normal in Deaver. The highest temperature was 92 degrees in Torrington, while the lowest temperature was 28 degrees in Big Piney. Nearly all areas received below normal precipitation, except many areas in the Platte River drainages which received nearly one-third to one-half inch above normal precipitation. The most precipitation fell in Torrington with 1.91 inches and 1.84 in Redbird.

Weather Summary: For the week ending Friday, September 17, a hard freeze was reported in the Southwest. Temperatures were mostly above normal throughout the State except in the Big Horn Drainage area. Temperatures ranged from 2.6 degrees below normal in Afton to 4.1 degrees above normal in Cheyenne. The highest temperature was 93 degrees in Newcastle, while the lowest temperature was 25 degrees in Big Piney. A trace or more of precipitation was reported in all areas, with some areas of Central and Northeastern Wyoming receiving above normal amounts. The most precipitation fell in Gillette with 1.15 inches and 1.01 in Archer.

Weather Summary: For the week ending Friday, September 24, temperatures were mostly below normal except in some eastern parts. Temperatures ranged from 5.4 degrees below normal in Deaver to 3.8 degrees above normal in Redbird. The highest temperature was 95 degrees in Torrington, while the lowest temperature was 21 degrees in Big Piney. A trace or more of precipitation was reported in all areas with most areas, particularly Southeast and South Central, receiving above normal amounts. The most precipitation fell in Wheatland with 1.47 inches and Torrington with 1.01 inches.

Weather Summary: For the week ending Friday, October 1, temperatures averaged mostly above normal except in some mostly Southeastern areas. Temperatures ranged from 2.1 degrees below normal in Wheatland to 6.6 degrees above normal in Jackson. The highest temperature was 83 degrees in Newcastle, while the lowest temperature was 20 degrees in Recluse. Significant precipitation was reported with most areas, except the Northeast, receiving above normal amounts. The most precipitation fell in Chugwater with 1.95 inches, Kaycee with 1.33 inches, and Wheatland with 1.20 inches.

Cheyenne

The average temperature in September was 58.7°F. This is 2.1°F above normal for the month. The maximum temperature for the month was 88°F on the 2nd and the minimum of 36°F occurred on the 22nd and 23rd. Precipitation total of 3.06 inches is 214 percent of normal and this represents the 7th wettest September since 1915 and the wettest September since 1995. A trace of snow fell on the 22nd.

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    Laramie

    The average temperature in September was 52.2°F. This is 0.7°F cooler than normal. The maximum temperature for the month was 80°F on the 1st, 2nd, and 3rd and the minimum for the month was 31°F occurring on the 22nd. Precipitation total of 3.03 inches is 306 percent of normal and this represents the wettest September since 1948. A record 0.91 inch fell on the last day of the month. A trace of snow fell on the 22nd although amounts up to 6 inches fell in the nearby mountains.

    Rawlins

    The average temperature in September was 55.4°F. This is 1.5°F cooler than normal. The maximum temperature for the month was 84°F on the 1st and the minimum for the month was 33°F occurring on the 21st. Precipitation total of 2.25 inches is 274 percent of normal and this represents the 3rd wettest September since 1951. A record 0.45 inch fell on the last day of the month.

    Rock Springs

    The average temperature in September was 56.0°F. This is 1.1°F warmer than normal. The maximum temperature for the month was 87°F on the 1st and the minimum for the month was 30°F occurring on the 21st. Precipitation total of 1.54 inches is 177 percent of normal.

    Evanston

    The average temperature in September was 53.9°F. This is 1.1°F warmer than normal. The maximum temperature for the month was 84°F on the 1st and the minimum for the month was 27°F occurring on the 22nd. Precipitation total of 0.61 inch is 48 percent of normal.

    Big Piney

    The average temperature in September was 49.2°F. This is 0.7°F warmer than normal. The maximum temperature for the month was 84°F on the 1st and the minimum for the month was 21°F occurring on the 22nd. Precipitation total of 1.37 inches is 167 percent of normal.

    Lander

    The average temperature in September was 58.6°F. This is 0.1°F cooler than normal. The maximum temperature for the month was 90°F on the 1st and the minimum for the month was 31°F occurring on the 22nd. Precipitation total of 1.08 inches is 95 percent of normal. A record 0.53 inch fell on the 29th.

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    Riverton

    The average temperature in September was 58.7°F. This is 1.4°F warmer than normal. The maximum temperature for the month was 90°F on the 1st and the minimum for the month of 30°F occurred on the 22nd. Precipitation total of 1.21 inches is 138 percent of normal. A record 0.36 inch fell on the 29th.

    Worland

    The average temperature in September was 58.6°F. This is 1.8°F cooler than normal. The maximum temperature for the month was 95°F on the 1st and the minimum for the month of 33°F occurred on the 15th. Precipitation total of 1.06 inches is 139 percent of normal.

    Sheridan

    The average temperature in September was 57.7°F. This is 0.6°F warmer than normal. The maximum temperature for the month was 97°F on the 1st and the minimum for the month of 30°F occurred on the 22nd. Precipitation total of 2.20 inches is 159 percent of normal.

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    Casper

    The average temperature in September was 58.6°F. This is 1.0°F warmer than normal. The maximum temperature for the month was 91°F on the 1st and the minimum for the month of 32°F occurred on the 23rd. Precipitation total of 1.75 inches is 179 percent of normal.

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    Douglas

    The average temperature in September was 59.2°F. This is 1.1°F warmer than normal. The maximum temperature for the month was 93°F on the 1st and the minimum for the month of 34°F occurred on the 23rd. Precipitation total of 2.31 inches is 216 percent of normal.

    Torrington

    The average temperature in September was 62.0°F. This is 2.3°F warmer than normal. The maximum temperature for the month was 95°F on the 18th and the minimum for the month of 37°F occurred on the 28th. Precipitation total of 4.03 inches is 317 percent of normal and this represents the 2nd wettest September on record (since 1922)!. The amount of 4.71 inches in September 1973 holds the record. A total of 1.47 inches fell on the 5th.

    Additional Stations:

    Buffalo
    Gillette
    Greybull

    This information was compiled by the Wyoming State Climatologist, University of Wyoming. For more information, contact Jan Curtis at (307) 766-6659. For periodic updates, visit http://www.wrds.uwyo.edu This site includes a searchable database for Wyoming climate and water. For additional daily and hourly climatology, click on historical at the bottom of the daily summary statistics. For Casper, Lander, and Riverton's Monthly F6 reports, see here and at the bottom of this webpage. Record daily temperatures are based on the period since 1948-9 for all cities unless otherwise noted.

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    Wyoming State Climatologist The Wyoming State Climatologist Office is funded by the Wyoming Water Development Commission

    WEBMASTER: stateclim@wrds.uwyo.edu
    Last reviewed or update: October 4, 2004

    		 Water Resources Data System