Pool season · Iowa
Cedar Rapids Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Cedar Rapids'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.
Cedar Rapids, IA — 75 swim days a yearEach dot on the bar is one week of Cedar Rapids'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 27–May 18), solid teal is swim season, and hollow amber is the closing window ending October 2. The black marker is today — its position against the colors is the entire executive summary.
The Cedar Rapids 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 2
The window opens September 22 once water leaves the algae zone; the model deadline is October 2, a week ahead of the October 11 freeze normal.
Estimated water temperature by month
This is Cedar Rapids'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 21° | 21° | 31° | 44° | 55° | 66° | 72° | 72° | 68° | 57° | 43° | 30° |
The curve peaks near 73°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Waterloo's pool season and Davenport's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Iowa season index.
Cedar Rapids pool season FAQ
When should I open my pool in Cedar Rapids, IA?
The site model recommends opening by May 4 — about two weeks before Cedar Rapids's 7-day mean temperature crosses 61°F, while the water is still too cold for algae. The step-by-step sequence is in the Cedar Rapids opening guide.
When should I close my pool in Cedar Rapids?
Winterize by October 2. The model holds the deadline a week ahead of Cedar Rapids's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Cedar Rapids closing guide.
How long is the swim season in Cedar Rapids?
Cedar Rapids averages 75 days a year with normal highs of 80°F or better — right on the statewide median. The Iowa season index ranks all 6 covered cities by the same metric.
How warm does pool water get in Cedar Rapids?
An unheated pool near Cedar Rapids typically peaks around 73°F in high summer and bottoms out near 20°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 Cedar Rapids hits the closing window
Data: NOAA 1991–2020 climate normals via Cedar Rapids Municipal Airport (6.1 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.