Wyoming Pool Season: Opening & Closing Dates by City

Local dates for every featured Wyoming city — when the water warms up, when it cools off, and how long the season actually lasts.

City Opening window Closing window Season
Cheyenne Jun 14 – Jul 10 Aug 6 – Sep 4 ≈ 59 days
Casper Jun 8 – Jun 29 Aug 23 – Sep 9 ≈ 75 days
Jackson Heater territory — peaks in July —

Windows show the stretch when each city's daily average passes through the low-to-mid 60s°F (1991–2020 NOAA records, nearest station to each city). Click a city for its month-by-month table and full season notes.

Season geography

Across Wyoming's featured cities, typical openings spread from Jun 17 to Jun 26, closings from Aug 24 to Sep 1, and the unheated season runs 0–75 days depending on where you are. In Jackson, unheated outdoor swimming never quite arrives — those pages cover the heater math instead. Elevation, coastal water, and urban heat all pull real dates around, which is exactly why a state-level answer isn't enough.

For your exact town, the pool season lookup takes a ZIP code. Opening day itself is a chemistry job — the dosing calculator turns your first test reading of the year into exact amounts.

Wyoming planning pages

When to open — Wyoming When to close — Wyoming All states →