Preliminary
Wyoming Monthly Climatology
May 2005
Statewide Summary
Graphs show that during the month of May, temperatures ranged from a few degrees above normal over SW Wyoming to about 5 degrees below normal over the tri-county region of Goshen, Platte, and Niobrara Counties. Precipitation was general above normal over the western and northern half of the state. Since the Water Year began on 1 October 2004, nearly half the counties in Wyoming have had near or above normal precipitation. Modeled soil moisture showed some more improvement over Wyoming during the month, with driest conditions persisting over northeastern Wyoming. Pasturelands (by area) improved 41% during the month. The end of May streamflow (7-day average) was near or above normal for most stations with the exception of below normal readings over northeastern Wyoming.
Weather Summary: For the week ending Friday, May 6, temperatures were below normal for the State. Temperatures ranged from 11.1°F below normal in Newcastle to 1.6°F below normal in Afton. The low temperature for the week was recorded in Laramie at 8°F, and the high temperature was 81°F in Redbird. Areas in the West and Southeast received small amounts of precipitation. The most precipitation fell in Afton with 0.78 inch, Evanston with 0.57 inch, and Torrington with 0.30 inch. Over the weekend, other areas including the Northeast received much-needed rain.
A strong Pacific Storm brought in two days time the equivalent of the precipitation received in an average May to areas east of
the Continental Divide. This storm system slowly moved overtop the Cowboy State on May 10th & 11th.
Weather Summary: For the week ending Friday, May 13, temperatures were below normal for the State. Temperatures ranged from 8.4°F below normal in Cody and Sundance to 0.8°F above normal in Jackson. The low temperature for the week was recorded in Archer at 19°F, and the high temperature was 81°F in Newcastle. Except a few southeastern stations, all areas received much higher than normal precipitation. Many areas, especially in the North received large amounts of precipitation. The most precipitation fell in Sheridan with 5.92 inches (probably exceeding a 100 to 250 year return period), Kaycee with 3.06 inches, Lander with 2.87 inches, and Cody with 2.86 inches. Rock Springs with 1.00 inches, and Wheatland with 0.97 inches.
Weather Summary: For the week ending Friday, May 20, temperatures were above normal for the State. Temperatures ranged from 0.3°F below normal in Powell to 7.6°F above normal in Cheyenne. The high temperature of the week was 95°F in Torrington and the low was 27°F in Laramie. Precipitation was generally below normal. The most precipitation fell in Deaver with 0.87 inch, Powell with 0.68 inch, and Afton with 0.65 inch.
Weather Summary: For the week ending Friday, May 27, temperatures were above normal for the State except for the North-western corner and some North-central areas. Temperatures ranged from 2.6°F below normal in Greybull to 6.9°F above normal in Archer. The high temperature of the week was 91°F in Archer and the low was 26°F in Big Piney. Precipitation was below normal for the State. The most precipitation fell in Newcastle with 0.78 inch, Redbird with 0.30 inch, and Torrington with 0.24 inch.
Memorial Weekend Rain and Snow Event: A Low Pressure system brought another round of rain and snow showers across the Cowboy State...bringing impressive amounts of moisture to the region.
Preliminary Severe Weather Reports: reference
Day..Time....Hail.......location...........................county.....................remarks (receiving NWSFO)
31......2235.....75......5 N THERMOPOLIS........HOT SPRINGS.....MOSTLY 1/2 INCH HAIL STONES BUT SOME 3/4 INCH HAIL STONES MIXED IN. (RIW)
23......0110.....75......4 E YODER.......................GOSHEN...............(CYS)
22......2250....100.....9 W ALBIN.......................LARAMIE..............(CYS)
10......2158.....75......KINNEAR.........................FREMONT............(RIW)
10......2308.....75......9 ESE LARAMIE...............ALBANY...............REPORTED BY FRITO-LAY DRIVER WHO WAS ON I-80 (CYS)
10......0322.....75......2 SSE CHEYENNE...........LARAMIE.............(CYS)
10......0355.....88.....10 E CHEYENNE...............LARAMIE.............(CYS)
09......2315.....75......5 NW MANDERSON.......BIG HORN............(RIW)
key: All Times UTC, Wind Gusts in MPH, Hail Sizes in 1/100 of an Inch (75 = 0.75")
Cheyenne
The average temperature in May was 52.1°F. This is 0.8°F warmer than normal for the month. The maximum temperature for the month was 86°F on the 20th and the minimum of 25°F occurred on the 12th. Precipitation total of 1.29 inches is 52% of normal. The wettest day in the was on the 30th (0.66 inch fell). Snowfall totaled 0.3 inches (all on the 11th) which is 10% of the long term average.
past 30-days precipitation
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Laramie
The average temperature in May was 47.3°F. This is 0.3°F warmer than normal for the month. The maximum temperature for the month was 82°F on the 20th (record tied for the day) and the minimum of 14°F occurred on the 1st. Another record high of 79°F occurred on the 22nd. Precipitation total of 1.06 inches is 63% of normal. The wettest day in the was on the 11th (0.41 inch fell).
Rawlins
The average temperature in May was 49.2°F. This is 1.7°F cooler than normal for the month. The maximum temperature for the month was 82°F on the 20th and the minimum for the month was 21°F occurring on the 1st and 2nd. Precipitation total of 1.56 inches is 105% of normal. The wettest day in the was on the 7th-8th (0.64 inch fell).
Rock Springs
The average temperature in May was 49.9°F. This is 0.8°F warmer than normal for the month. The maximum temperature for the month was 82°F on the 20th and the minimum for the month was 24°F occurring on the 1st. Precipitation total of 1.95 inches is 147% ofnormal. Snowfall totaled 2.5 inches (1.5 inches fell on the 11th) which is 125% of the long term average.
Evanston
The average temperature in May was 48.3°F. This is 0.8°F warmer than normal for the month. The maximum temperature for the month was 76°F on the 20th and the minimum for the month was 27°F occurring on the 2nd. Precipitation total of 2.82 inches is 192% of normal.
Big Piney
The average temperature in May was 46.3°F. This is 0.3°F warmer than normal for the month. The maximum temperature for the month was 76°F on the 20th and the minimum for the month was 18°F occurring on the 1st. Precipitation total of 2.61 inches is 258% of normal. The wettest day in the was on the 29th-30th (0.83 inch fell).
Lander
The average temperature in May was 52.2°F. This is 1.2°F cooler than normal for the month. The maximum temperature for the month was 83°F on the 20th and the minimum for the month was 25°F occurring on the 2nd. Precipitation total of 4.34 inches is 187% of normal. The wettest day in the was on the 10th-11th (2.26 inches fell). Snowfall totaled 0.3 inch (all falling on the 11th) which is 5% of the long term average. Snowfall since 1 July 04 is 87.3 inches.
past 30-days precipitation
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Riverton
The average temperature in May was 52.4°F. This is 1.4°F cooler than normal. The maximum temperature for the month was 84°F on the 20th and the minimum for the month of 24°F occurred on the 2nd. Precipitation total of 3.17 inches is 183% of normal. The wettest day in the was on the 10th-11th (1.15 inches fell). No snow was reported for the month but for the season (since 1 July 04) 37.5 inches has occurred.
Worland
The average temperature in May was 53.6°F. This is 4.0°F cooler than normal for the month. The maximum temperature for the month was 88°F on the 20th and the minimum for the month of 0°F occurred on the 10th. Precipitation total of 2.61 inches is 161% of normal. The wettest day in the was on the 7th (0.76 inch fell).
Sheridan
The average temperature in May was 51.0°F. This is 1.5°F cooler than normal for the month. The maximum temperature for the month was 83°F on the 20th and the minimum for the month of 16°F occurred on the 2nd. Precipitation total of 6.18 inches is 256% of normal and represents the 2nd wettest May on record (6.80 inches in 1978 still standssince 1949). The wettest day in the was on the 10th-11th (2.53 inches fell).
past 30-days precipitation
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Casper
The average temperature in May was 50.6°F. This is 1.5°F cooler than normal. The maximum temperature for the month was 87°F on the 20th and the minimum for the month of 17°F occurred on the 1st and 2nd. Precipitation total of 2.63 inches is 114% of normal. The wettest day in the was on the 10th-11th (0.99 inch fell). Snowfall totaled 2.0 inches (all on the 11th) which is 51% of the long term average. Since 1 July 04, a total of 59.3 inches of snow has been recorded in Casper.
past 30-days precipitation
past 30-days temperature
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Douglas
The average temperature in May was 51.2°F. This is 1.9°F cooler than normal for the month. The maximum temperature for the month was 89°F on the 20th (record for the day) and the minimum for the month of 17°F occurred on the 2nd. Precipitation total of 2.53 inches is 101% of normal. The wettest day in the was on the 29th-30th (0.71 inch fell).
Torrington
The average temperature in May was 54.7°F. This is 1.5°F cooler than normal for the month. The maximum temperature for the month was 95°F on the 20th (record for the day) and the minimum for the month of 20°F occurred on the 2nd. Precipitation total of 2.08 inches is 82% of normal. The wettest day in the was on the 29th-30th (1.03 inch fell).
Additional Summaries:
Cody:......average temperature 51.1°F, max for month 81°F (22nd), min for month 21°F (2nd), precip total (2.95 inches).
Buffalo:....average temperature 49.6°F, max for month 83°F (20th), min for month 17°F (2nd), precip total (6.39 inches) record 7.86 inches in 1978 still holds.
Greybull:..average temperature 55.1°F, max for month 87°F (20th), min for month 26°F (2nd), precip total (2.89 inches).
Jackson:..average temperature 45.9°F, max for month 73°F (20th), min for month 19°F (2nd).
Yellowstone Lake:... average temperature 38.9°F, max for month 65°F (28th), min for month 1°F (11th), precip total (2.62 inches).
Gillette:.....average temperature 50.3°F, max for month 84°F (20th), min for month 15°F (2nd), precip total (2.89 inches).
Additional Stations (daily summary):
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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