Pool closing · State guide
When to Close Your Pool in Missouri
Last updated: July 15, 2026 · 8 cities covered
Closing deadlines across Missouri stretch about 10 days: Independence needs the cover on first (October 13), St. Louis last (October 23), and the statewide median deadline is October 17.
Each deadline is the model's two-clock compromise — ten days after the water leaves the algae zone, capped a week before the local 50% first-freeze date. City pages carry the live widget that flags early-freeze years and the full winterizing sequence.
| City | Window opens | Close by | First freeze (50%) |
|---|---|---|---|
| Columbia | Oct 7 | Oct 17 | Oct 31 |
| Independence | Oct 3 | Oct 13 | Oct 27 |
| Joplin | Oct 11 | Oct 20 | Oct 27 |
| Kansas City | Oct 10 | Oct 20 | Nov 2 |
| Lee's Summit | Oct 6 | Oct 16 | Oct 29 |
| O'Fallon | Oct 4 | Oct 14 | Oct 26 |
| Springfield | Oct 8 | Oct 18 | Oct 27 |
| St. Louis | Oct 13 | Oct 23 | Nov 4 |
Dates are typical-year model outputs, not forecasts — each city guide carries the live widget that tracks the current year against them.
How to use these dates
Each "close by" deadline is the model's two-clock compromise for that city: ten days after its 7-day mean temperature falls back through 61°F (water goes algae-dormant soon after), but never later than a week before its 50% first-freeze date from the NOAA 1991–2020 normals. Closing inside the window seals cold, stable water under the cover; closing early seals a warm algae incubator instead.
Treat the dates as typical-year guidance, not forecasts. An early cold snap moves the real deadline — each city guide runs a live water-temperature widget that flags a 32°F night inside the 10-day forecast as urgent, and carries the full winterizing checklist in working order.