Pool season · Iowa
Des Moines Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
This is the one-page view of Des Moines'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.
Each dot on the bar is one week of Des Moines'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 22–May 13), solid teal is swim season, and hollow amber is the closing window ending October 8. The black marker is today — its position against the colors is the entire executive summary.
The Des Moines pool calendar
Opening — target April 29
Target April 29; the practical window runs April 22–May 13, and the 7-day mean crosses the 61°F threshold around May 13. Cold-water starts are the cheap ones.
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 20 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Des Moines'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° | 68° | 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 Des Moines hits the closing window
Data: NOAA 1991–2020 climate normals via Des Moines International Airport (3.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.