Pool season · Montana
Billings Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Billings pool. The season bar below draws everything the model knows — opening window, prime season, closing window — against today's date, with the working details one click away on the opening and closing pages.
The bar compresses Billings's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the May 13–June 3 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends September 27. Wherever the today marker sits, the nearest color change is your next appointment.
The Billings pool calendar
Opening — target May 20
Open by May 20 — a two-week head start on the June 3 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline September 27
The window opens September 17 once water leaves the algae zone; the model deadline is September 27, a week ahead of the October 7 freeze normal.
Estimated water temperature by month
This is Billings's typical-year water curve: the same EWMA model as the live widget, run on the 1991–2020 normals instead of this week's weather.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 27° | 28° | 34° | 43° | 51° | 61° | 70° | 74° | 67° | 55° | 41° | 31° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Billings hits the closing window
Data: NOAA 1991–2020 climate normals via Billings Logan International Airport (1.3 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.