Preliminary
Wyoming Monthly Climatology
May 2003
Statewide Summary
Temperatures for the month of May were above normal across much of Wyoming. Average temperatures ranged from >3 degrees at Rock Springs to 1 degree below normal in Sheridan. Precipitation for the month of May also showed large variation across the state. The heaviest moisture amounts fell in portions of north central and extreme southwest Wyoming (>150 percent), the least over Sweetwater County (<5 percent). Some precipitation helped grasslands grow over the eastern third of the state but the long term hydrological drought persists across most of Wyoming. During the past year, much of Wyoming has experienced well below normal precipitation especially over the southwestern part of the state. Soil moisture negative departure from long term means are noted over southwest Wyoming with positive departures over portions of northeastern Wyoming. At Torrington in eastern Wyoming, soil moisture, especially near the surface, has declined in May.
The average temperature in May 2003 was 51.9°F. This was 2.3°F warmer
than the 1895-2003 average, the 24th warmest May in 109 years. The
temperature trend for the period of record (1895 to present) is 0.2
degree Fahrenheit per decade.
1.19 inches of precipitation fell in May. This was -0.79 inch less
than the 1895-2003 average, the 16th driest such month on record. The
precipitation trend for the period of record (1895 to present) is -0.03
inch per decade.
Cheyenne
The average temperature in May was 53.5°F. This is 2.2°F warmer than normal. The maximum for the month was 91 °F on the 29th (tied for all time May maximum temperature) and the minimum of 16°F occurred on the 11th. Precipitation total of 1.41 inches is 57 percent of normal. Snowfall totaled 2.4 inches which is 96 percent of the long term average.
past 30-days precipitation
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Laramie
The average temperature in May was 48.0°F. This is 1.6°F warmer than normal. The maximum for the month was 87°F on the 29th (new all time May maximum temperature) and the minimum for the month was 16°F that occurred on the 11th. Precipitation total of 1.73 inches is 104 percent of normal.
Rawlins
The average temperature in May was 50.4°F. This is 0.5°F colder than normal. The maximum temperature for the month was 86°F on the 29th (record for the day) and the minimum temperature for the month of 24°F occurred on the 10th. Precipitation total of 1.47 inches is 99 percent of normal.
Rock Springs
The average temperature in May was 52.6°F. This is 3.3°F warmer than normal. The maximum temperature for the month was 89°F on the 28th and 29th (both records for the day) and the minimum of 23°F occurred on the 6th. Precipitation total of 0.90 inch is 66 percent of normal. Snowfall totaled 6.4 inches which is 320 percent of the long term average.
Evanston
The average temperature in May was 50.0°F. This is 2.5°F warmer than normal. The maximum temperature for the month was 85°F on the 29th and the minimum of 24°F occurred on the 6th and 19th. Precipitation total of 1.26 inches is 86 percent of normal. Snowfall totaled 9.5 inches which is 475 percent of the long term average. There have been several May totals exceeding 12 inches during the period of record in Evanston.
Big Piney
The average temperature in May was 47.1°F. This is 1.1°F warmer than normal. The maximum temperature for the month was 86°F on the 28th (all time daily May record) and the minimum of 12°F occurred on the 6th. Other record highs were set on the 26th (80°F), 27th (82°F), 29th (85°F), and 30th (81°F). The last week in May saw rapid mountain snowmelt across Wyoming with many streams exceeding their maximum flow for this period. Precipitation total of 0.58 inch is 57 percent of normal. Snowfall totaled 3.1 inches which is 238 percent of the long term average.
Lander
The average temperature in May was 54.4°F. This is 1.0°F warmer than normal. The maximum temperature for the month was 93°F on the 29th (all time daily May temperature) and the minimum for the month of 28°F occurred on the 20th. Other record temperatures occurred on the 26th (86°F) and on the 28th (90°F). Precipitation total of 1.28 inches is 54 percent of normal. Snowfall totaled 3.9 inches which is 55 percent of the long term average.
past 30-days precipitation
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Riverton
The average temperature in May was 55.3°F. This is 1.5°F warmer than normal. The maximum temperature for the month was 93°F on the 29th and the minimum for the month of 26°F occurred on the 20th. Another record high of 90°F was set on the 28th. Precipitation total of 1.03 inches is 58 percent of normal. Snowfall totaled 1.3 inches which is 325 percent of the long term average.
Worland
The average temperature in May was 56.3°F. This is 1.0°F colder than normal. The maximum temperature for the month was 94°F on the 29th (record for the day) and the minimum of 30°F occurred on the 20th (record for the day). Precipitation total of 1.12 inches is 76 percent of normal.
Sheridan
The average temperature in May was 51.6°F. This is 0.9°F colder than normal. The maximum temperature for the month was 88°F on the 29th and the minimum for the month of 28°F occurred on the 19th (tied for record of the day) and 20th (record for the day). Precipitation total of 1.46 inches is 61 percent of normal. Snowfall totaled 2.4 inches which is 141 percent of the long term average.
past 30-days precipitation
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Casper
The average temperature in May was 53.3°F. This is 1.2°F warmer than normal. The maximum temperature for the month was 95°F on the 29th (all time May daily high temperature record) and the minimum for the month of 23°F occurred on the 7th. Other record temperatures occurred on the 28th (92°F) and on the 20th (24°F). Precipitation total of 0.51 inch is 21 percent of normal. Snowfall totaled 0.4 inch which is 8 percent of the long term average.
past 30-days precipitation
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Torrington
The average temperature in May was 57.3°F. This is 1.3°F warmer than normal. The maximum temperature for the month was 100°F on the 29th (tied for all time May record high temperature) and the minimum for the month of 25°F occurred on the 20th. Precipitation total of 1.29 inches is 51 percent of normal.
Additional Stations:
Buffalo
Douglas
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 this interactive map by selecting a city. Then click on the "Monthly History" link on the left menu. Record daily temperatures are based on the period since 1948-9 for all cities unless otherwise noted.
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