Pool season · Arizona
Surprise Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Surprise'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.
Surprise, AZ — 210 swim days a yearThe bar compresses Surprise's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the February 27–March 20 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 22. Wherever the today marker sits, the nearest color change is your next appointment.
The Surprise pool calendar
Opening — target March 6
Open by March 6 — a two-week head start on the March 20 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 22
The window opens November 12 once water leaves the algae zone; the model deadline is November 22, a week ahead of the December 11 freeze normal.
Estimated water temperature by month
This is Surprise'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 52° | 53° | 58° | 63° | 71° | 81° | 89° | 91° | 88° | 78° | 66° | 54° |
Warmest water typically June–October (peaking near 91°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Scottsdale's pool season and Tempe's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Arizona season index.
Surprise pool season FAQ
When should I open my pool in Surprise, AZ?
Target March 6. That date backs off two weeks from the day Surprise's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Surprise opening guide.
When should I close my pool in Surprise?
The closing deadline is November 22 — late enough that the water has cooled out of the algae zone, early enough to beat Surprise's first-freeze normal by about a week. See the Surprise closing guide for the winterizing steps.
How long is the swim season in Surprise?
Surprise averages 210 days a year with normal highs of 80°F or better — about 9 days later than the Arizona median. The Arizona season index ranks all 20 covered cities by the same metric.
How warm does pool water get in Surprise?
An unheated pool near Surprise typically peaks around 91°F in high summer and bottoms out near 51°F in winter, spending roughly 4 months 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 Surprise hits the closing window
Data: NOAA 1991–2020 climate normals via Wittmann 1se (7.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.