Pool season · Illinois
Bloomington Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
Bloomington'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.
The bar compresses Bloomington's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 23–May 14 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 8. Wherever the today marker sits, the nearest color change is your next appointment.
The Bloomington pool calendar
Opening — target April 30
Open by April 30 — a two-week head start on the May 14 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 8
The window opens September 28 once water leaves the algae zone; the model deadline is October 8, a week ahead of the October 16 freeze normal.
Estimated water temperature by month
This is Bloomington'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 26° | 26° | 34° | 45° | 57° | 68° | 74° | 74° | 70° | 60° | 47° | 34° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Bloomington hits the closing window
Data: NOAA 1991–2020 climate normals via Normal 4ne (5.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.