Pool closing · State guide
When to Close Your Pool in Arizona
Last updated: July 15, 2026 · 20 cities covered
Closing deadlines across Arizona stretch about 81 days: Flagstaff needs the cover on first (September 17), Yuma last (December 7), and the statewide median deadline is November 25.
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%) |
|---|---|---|---|
| Avondale | Nov 17 | Nov 27 | Dec 24 |
| Buckeye | Nov 17 | Nov 27 | Dec 24 |
| Casas Adobes | Nov 13 | Nov 23 | Dec 4 |
| Chandler | Nov 18 | Nov 28 | Dec 5 |
| Flagstaff | Sep 7 | Sep 17 | Sep 28 |
| Gilbert | Nov 13 | Nov 23 | Dec 11 |
| Glendale | Nov 14 | Nov 24 | Dec 15 |
| Goodyear | Nov 20 | Nov 30 | Dec 22 |
| Maricopa | Nov 14 | Nov 17 | Nov 24 |
| Mesa | Nov 18 | Nov 28 | Dec 10 |
| Peoria | Nov 12 | Nov 22 | Dec 11 |
| Phoenix | Nov 18 | Nov 28 | Dec 25 |
| Prescott Valley | Oct 3 | Oct 13 | Oct 20 |
| Queen Creek | Nov 13 | Nov 23 | Dec 11 |
| San Tan Valley | Nov 13 | Nov 23 | Dec 11 |
| Scottsdale | Nov 16 | Nov 26 | Dec 21 |
| Surprise | Nov 12 | Nov 22 | Dec 11 |
| Tempe | Nov 18 | Nov 28 | Dec 5 |
| Tucson | Nov 16 | Nov 26 | Dec 9 |
| Yuma | Nov 27 | Dec 7 | Dec 28 |
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.