Pool season · Michigan
Dearborn Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
Dearborn's whole pool calendar, condensed: when the water warms, when it cools, and where today falls between those edges. Use the opening guide and closing guide for the step-by-step work; keep this page for the dates.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Dearborn's swim season; the hollow teal run before it (May 2 to May 23) is when to open; the hollow amber run after is when to close, with October 4 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Dearborn pool calendar
Opening — target May 9
Target May 9; the practical window runs May 2–May 23, and the 7-day mean crosses the 61°F threshold around May 23. Cold-water starts are the cheap ones.
Closing — deadline October 4
The window opens September 24 once water leaves the algae zone; the model deadline is October 4, a week ahead of the October 15 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Dearborn'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 27° | 25° | 31° | 42° | 54° | 64° | 72° | 72° | 68° | 58° | 46° | 35° |
The curve peaks near 73°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Dearborn hits the closing window
Data: NOAA 1991–2020 climate normals via Dearborn (1.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.