Pool season · Illinois
Arlington Heights Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Arlington Heights 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.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Arlington Heights's swim season; the hollow teal run before it (April 29 to May 20) is when to open; the hollow amber run after is when to close, with October 7 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Arlington Heights pool calendar
Opening — target May 6
Target May 6; the practical window runs April 29–May 20, and the 7-day mean crosses the 61°F threshold around May 20. Cold-water starts are the cheap ones.
Closing — deadline October 7
Hold the cover until September 27, then winterize by October 7, a week ahead of the October 26 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Arlington Heights'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° | 26° | 34° | 44° | 55° | 66° | 73° | 75° | 70° | 60° | 47° | 35° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Arlington Heights hits the closing window
Data: NOAA 1991–2020 climate normals via Chicago Palwaukee Airport (4.3 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.