Pool season · Michigan
Holland Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Holland 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.
Each dot on the bar is one week of Holland's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (May 3–May 24), solid teal is swim season, and hollow amber is the closing window ending October 1. The black marker is today — its position against the colors is the entire executive summary.
The Holland pool calendar
Opening — target May 10
Open by May 10 — a two-week head start on the May 24 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 1
The window opens September 21 once water leaves the algae zone; the model deadline is October 1, a week ahead of the October 21 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Holland's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 28° | 26° | 32° | 42° | 53° | 64° | 71° | 71° | 67° | 57° | 46° | 36° |
The curve peaks near 72°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Holland hits the closing window
Data: NOAA 1991–2020 climate normals via Holland Tulip City Airport (1.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.