Pool season · Illinois
Evanston Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Evanston 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 Evanston'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 5–May 26), solid teal is swim season, and hollow amber is the closing window ending October 5. The black marker is today — its position against the colors is the entire executive summary.
The Evanston pool calendar
Opening — target May 12
Open by May 12 — a two-week head start on the May 26 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 5
Hold the cover until September 25, then winterize by October 5, a week ahead of the October 21 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Evanston'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 26° | 25° | 33° | 43° | 53° | 64° | 72° | 73° | 69° | 59° | 46° | 35° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Evanston hits the closing window
Data: NOAA 1991–2020 climate normals via Chicago Botanic Garden (8.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.