Heat in North Big Horn Basin, Wyoming

Record warmth occurred over the latter half of March in Big Horn County. The period from March 17 through March 30 averaged more than 12 degrees above normal. Every day but one had above normal daily average temperatures, with ten days more than 10 degrees above normal. Seven new daily record high temperatures were set. The previous monthly record high temperature of 81 was tied or broken on three consecutive days from March 19 to March 21, including a new monthly record high temperature of 85 on March 21. The previous earliest occurrence of 80 degrees was broken by 12 days. Records at the South Big Horn County airport near Greybull date back to 1998.

A very strong ridge of high pressure set up across much of the western United States and brought an long period of record breaking warmth. The most impressive stretch was from March 18 through March 21. In total, 71 new daily record high temperatures were set out of a possible 126 high temperatures at RIW CLI sites (longer term climate sites), greater than half of the daily highs. Every location was at least 10 degrees above normal through the period. Every location had their all time warmest period for these two weeks, with three locations; the Riverton Airport, the Sweetwater County airport near Rock Springs, and the Lander airport; more than 8 degrees above the previous warmest period. All locations set their all time high temperature March multiple times in this stretch. Six locations had their earliest 80 degree high temperature, with four stations having their first 80 degree or greater March high temperatures in station history.