Pool season · Michigan
Grand Rapids Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Grand Rapids 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 Grand Rapids's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the May 4–May 25 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends September 29. Wherever the today marker sits, the nearest color change is your next appointment.
The Grand Rapids pool calendar
Opening — target May 11
Target May 11; the practical window runs May 4–May 25, and the 7-day mean crosses the 61°F threshold around May 25. Cold-water starts are the cheap ones.
Closing — deadline September 29
Hold the cover until September 19, then winterize by September 29, a week ahead of the October 10 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Grand Rapids'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 26° | 24° | 30° | 41° | 52° | 64° | 70° | 71° | 66° | 56° | 44° | 34° |
The curve peaks near 72°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Grand Rapids hits the closing window
Data: NOAA 1991–2020 climate normals via E Grand Rapids (2.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.