Heat wave in Wyoming and neighboring states

In late July 2026 the National Weather Service first issued a Heat Advisory for the I‑25 corridor spanning southeast Wyoming, eastern Nebraska and parts of Idaho, warning of daytime temperatures approaching 100 °F and warm overnight lows, along with a Red Flag Warning for fire‑prone areas of the Upper Snake River Plain. A week later, the Cheyenne office warned of near‑record highs of 96‑97 °F in southeast Wyoming as monsoonal moisture retreated, noting persistent high‑pressure, breezy conditions and the potential for wildfire smoke drifting in from Oregon.

By July 29 the advisories were expanded to additional locations in Wyoming and into Colorado. In Jackson Hole a valley‑floor heat advisory ran from Saturday noon through Sunday night, with expected highs of 98‑105 °F below 5,500 ft and 90‑98 °F above. Southeast Wyoming, including Cheyenne, was forecast to see near‑record temperatures near 96 °F on Sunday, with a heat advisory beginning Saturday and a chance of isolated thunderstorms. In Colorado, Cheyenne Wells faced fire‑danger conditions as temperatures were projected to reach 102 °F on Monday, humidity in the teens and gusts up to 40 mph, prompting warnings to avoid activities that could spark wildfires. Officials continued to urge residents to stay hydrated, limit outdoor activity, and check on vulnerable neighbors as fire risk remained elevated.