Pool season · Illinois
Rockford Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
This is the one-page view of Rockford's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Rockford's swim season; the hollow teal run before it (April 27 to May 18) is when to open; the hollow amber run after is when to close, with October 4 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Rockford pool calendar
Opening — target May 4
Target May 4; the practical window runs April 27–May 18, and the 7-day mean crosses the 61°F threshold around May 18. Cold-water starts are the cheap ones.
Closing — deadline October 4
Hold the cover until September 24, then winterize by October 4, a week ahead of the October 17 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Rockford'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 24° | 23° | 32° | 44° | 55° | 66° | 73° | 73° | 69° | 58° | 45° | 32° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Rockford hits the closing window
Data: NOAA 1991–2020 climate normals via Rockford Gtr Rockford Airport (4.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.