Pool season · Michigan
Flint Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Flint'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.
Flint, MI — 47 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Flint's swim season; the hollow teal run before it (May 6 to May 27) is when to open; the hollow amber run after is when to close, with September 28 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Flint pool calendar
Opening — target May 13
Target May 13; the practical window runs May 6–May 27, and the 7-day mean crosses the 61°F threshold around May 27. Cold-water starts are the cheap ones.
Closing — deadline September 28
Hold the cover until September 18, then winterize by September 28, a week ahead of the October 13 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Flint'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 25° | 23° | 29° | 40° | 52° | 63° | 70° | 70° | 66° | 56° | 44° | 33° |
The curve peaks near 71°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Farmington Hills's pool season and Grand Rapids's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Michigan season index.
Flint pool season FAQ
When should I open my pool in Flint, MI?
Target May 13. That date backs off two weeks from the day Flint's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Flint opening guide.
When should I close my pool in Flint?
The closing deadline is September 28 — late enough that the water has cooled out of the algae zone, early enough to beat Flint's first-freeze normal by about a week. See the Flint closing guide for the winterizing steps.
How long is the swim season in Flint?
Flint averages 47 days a year with normal highs of 80°F or better — right on the statewide median. The Michigan season index ranks all 23 covered cities by the same metric.
How warm does pool water get in Flint?
An unheated pool near Flint typically peaks around 71°F in high summer and bottoms out near 23°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Flint hits the closing window
Data: NOAA 1991–2020 climate normals via Flint 7w (4.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.