Pool season · State index
Wyoming Pool Season 2026: Opening & Closing Dates by City
Last updated: July 25, 2026 · 1 cities covered
Both halves of the pool year for all 1 covered Wyoming cities. The median calendar runs May 28 to September 20. Every row links to a one-page season overview with the live water-temperature model; the opening and closing hubs carry the full checklists.
Wyoming: a short-season pool state| City | Open by | Close by | 80°F+ days |
|---|---|---|---|
| Cheyenne | May 28 | Sep 20 | 58 |
What the columns mean
"Open by" is the recommended spring date — two weeks before the city's 7-day mean temperature crosses 61°F, the model's proxy for water approaching the 65°F algae-growth zone. "Close by" is the fall deadline — ten days after the water leaves that zone, capped a week ahead of the local 50% first-freeze date. "80°F+ days" counts days whose normal high reaches 80°F: the length of the true warm-swim season, and the fairest single number for comparing Wyoming cities against each other.
Every figure comes from each city's own NOAA 1991–2020 normals station (named in its guide's footer), so neighboring cities can legitimately differ by a few days. The season overview linked from each row adds the live water-temperature model and the full-year season bar; the state hubs above carry the step-by-step checklists.
Swim-season length across Wyoming
The fairest way to compare Wyoming cities is the number of days with 80°F+ normal highs — the practical warm-swim season. Every bar links to that city's one-page season overview with the live water model.
Wyoming pool climate at a glance
High elevation and near-constant wind give Wyoming one of the nation's shortest seasons, and mountain towns can see frost even in the warmer months. In model terms that makes Wyoming a short-season state. The spread shows up clearly on the local pages: compare Cheyenne's pool season and the difference is measured in weeks, not days. Neighbors in the index run on their own normals too — see Wisconsin and Alabama for the adjacent calendars.
Wyoming pool season FAQ
When do pools open in Wyoming?
Model openings in Wyoming run from May 28 in Cheyenne to May 28 in Cheyenne, with the statewide median on May 28. Each date is two weeks before that city's 7-day mean temperature crosses 61°F — early enough to start up in algae-cold water.
When should you close a pool in Wyoming?
The median Wyoming closing deadline is September 20, and every city's own deadline is capped a week ahead of its NOAA 50% first-freeze date. Closing late and cold beats closing early and warm — cool water holds its winter chemistry far better.
Which Wyoming city has the longest swim season?
Cheyenne leads with 58 days of 80°F+ highs per year. The chart above ranks every covered city by the same metric.