Pool season · State index
Missouri Pool Season 2026: Opening & Closing Dates by City
Last updated: July 25, 2026 · 8 cities covered
Both halves of the pool year for all 8 covered Missouri cities. The median calendar runs April 17 to October 17. Every row links to a one-page season overview with the live water-temperature model; the opening and closing hubs carry the full checklists.
Missouri: a moderate-season pool state| City | Open by | Close by | 80°F+ days |
|---|---|---|---|
| Columbia | Apr 17 | Oct 17 | 109 |
| Independence | Apr 25 | Oct 13 | 101 |
| Joplin | Apr 14 | Oct 20 | 119 |
| Kansas City | Apr 16 | Oct 20 | 114 |
| Lee's Summit | Apr 20 | Oct 16 | 105 |
| O'Fallon | Apr 18 | Oct 14 | 106 |
| Springfield | Apr 19 | Oct 18 | 112 |
| St. Louis | Apr 11 | Oct 23 | 118 |
What the columns mean
"Open by" is the recommended spring date — two weeks before the city's 7-day mean temperature crosses 61°F, the model's proxy for water approaching the 65°F algae-growth zone. "Close by" is the fall deadline — ten days after the water leaves that zone, capped a week ahead of the local 50% first-freeze date. "80°F+ days" counts days whose normal high reaches 80°F: the length of the true warm-swim season, and the fairest single number for comparing Missouri cities against each other.
Every figure comes from each city's own NOAA 1991–2020 normals station (named in its guide's footer), so neighboring cities can legitimately differ by a few days. The season overview linked from each row adds the live water-temperature model and the full-year season bar; the state hubs above carry the step-by-step checklists.
Swim-season length across Missouri
The fairest way to compare Missouri cities is the number of days with 80°F+ normal highs — the practical warm-swim season. Every bar links to that city's one-page season overview with the live water model.
Missouri pool climate at a glance
Hot, humid summers push pool demand from May through September, but Missouri's volatile springs — late frosts one week and severe storms the next — make opening timing a judgment call. In model terms that makes Missouri a moderate-season state. The spread shows up clearly on the local pages: compare Joplin's pool season with Columbia's and the difference is measured in weeks, not days. Neighbors in the index run on their own normals too — see Mississippi and Montana for the adjacent calendars.
Missouri pool season FAQ
When do pools open in Missouri?
Model openings in Missouri run from April 11 in St. Louis to April 25 in Independence, with the statewide median on April 18. Each date is two weeks before that city's 7-day mean temperature crosses 61°F — early enough to start up in algae-cold water.
When should you close a pool in Missouri?
The median Missouri closing deadline is October 18, and every city's own deadline is capped a week ahead of its NOAA 50% first-freeze date. Closing late and cold beats closing early and warm — cool water holds its winter chemistry far better.
Which Missouri city has the longest swim season?
Joplin leads with 119 days of 80°F+ highs per year, while Independence brings up the rear at 101 days. The chart above ranks every covered city by the same metric.