Pool season · Iowa
Iowa City Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Iowa City 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.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Iowa City's swim season; the hollow teal run before it (April 21 to May 12) is when to open; the hollow amber run after is when to close, with October 8 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Iowa City pool calendar
Opening — target April 28
Open by April 28 — a two-week head start on the May 12 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 18 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Iowa City'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 24° | 24° | 34° | 46° | 57° | 69° | 75° | 75° | 70° | 60° | 46° | 33° |
The curve peaks near 76°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Iowa City hits the closing window
Data: NOAA 1991–2020 climate normals via Iowa City Municipal Airport (1.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.