Pool season · Illinois
Cicero Pool Season: the Year on One Bar
Last updated: July 25, 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.
Cicero, IL — 84 swim days a yearEach 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.
Every station tells its own story: compare this curve with Chicago's pool season and Decatur's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Illinois season index.
Cicero pool season FAQ
When should I open my pool in Cicero, IL?
Open by May 1 — the model places Cicero's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Cicero opening guide has the 12-step sequence.
When should I close my pool in Cicero?
Close by October 12: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Cicero closing guide sequences the work backward from that date.
How long is the swim season in Cicero?
Cicero averages 84 days a year with normal highs of 80°F or better — about 4 days earlier than the Illinois median. The Illinois season index ranks all 18 covered cities by the same metric.
How warm does pool water get in Cicero?
An unheated pool near Cicero typically peaks around 76°F in high summer and bottoms out near 26°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 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.