Pool season · Missouri
Columbia Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Columbia 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.
Columbia, MO — 109 swim days a yearEach dot on the bar is one week of Columbia'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 10–May 1), solid teal is swim season, and hollow amber is the closing window ending October 17. The black marker is today — its position against the colors is the entire executive summary.
The Columbia pool calendar
Opening — target April 17
Target April 17; the practical window runs April 10–May 1, and the 7-day mean crosses the 61°F threshold around May 1. Cold-water starts are the cheap ones.
Closing — deadline October 17
The window opens October 7 once water leaves the algae zone; the model deadline is October 17, a week ahead of the October 31 freeze normal.
Estimated water temperature by month
This is Columbia'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 32° | 33° | 41° | 52° | 62° | 71° | 78° | 79° | 74° | 63° | 51° | 40° |
Warmest water typically July–August (peaking near 79°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with St. Louis's pool season and Independence's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Missouri season index.
Columbia pool season FAQ
When should I open my pool in Columbia, MO?
Target April 17. That date backs off two weeks from the day Columbia's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Columbia opening guide.
When should I close my pool in Columbia?
The closing deadline is October 17 — late enough that the water has cooled out of the algae zone, early enough to beat Columbia's first-freeze normal by about a week. See the Columbia closing guide for the winterizing steps.
How long is the swim season in Columbia?
Columbia averages 109 days a year with normal highs of 80°F or better — right on the statewide median. The Missouri season index ranks all 8 covered cities by the same metric.
How warm does pool water get in Columbia?
An unheated pool near Columbia typically peaks around 79°F in high summer and bottoms out near 31°F in winter, spending roughly 1 month at or above the 78°F comfort line most swimmers prefer. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Columbia hits the closing window
Data: NOAA 1991–2020 climate normals via Columbia U Of M (0.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.