Pool season · Illinois
Cicero Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
Cicero'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.
Each dot on the bar is one week of Cicero's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (April 24–May 15), solid teal is swim season, and hollow amber is the closing window ending October 12. The black marker is today — its position against the colors is the entire executive summary.
The Cicero pool calendar
Opening — target May 1
Open by May 1 — a two-week head start on the May 15 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 12
Hold the cover until October 2, then winterize by October 12, a week ahead of the October 31 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Cicero'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° | 27° | 35° | 46° | 57° | 67° | 75° | 76° | 72° | 61° | 48° | 36° |
The curve peaks near 76°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Cicero hits the closing window
Data: NOAA 1991–2020 climate normals via Chicago Midway Airport (4.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.