Idaho Pool Season: Opening & Closing Dates by City

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

City Opening window Closing window Season
Boise May 24 – Jun 16 Sep 10 – Sep 25 ≈ 106 days
Idaho Falls Jun 13 – Jul 5 Aug 20 – Sep 9 ≈ 67 days
Coeur d’Alene Jun 17 – Jul 8 Aug 21 – Sep 11 ≈ 65 days

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 Idaho's featured cities, typical openings spread from Jun 4 to Jun 27, closings from Aug 30 to Sep 18, and the unheated season runs 65–106 days depending on where you are. 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.

Idaho planning pages

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