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Pool season · Arizona

Phoenix Pool Season: the Year on One Bar

Last updated: July 25, 2026 · dates · water temp

This is the one-page view of Phoenix'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.

Palm-lined pool deck in a warm year-round swim climatePhoenix, AZ — 212 swim days a year
J F M A M J J A S O N D today (build date)

off-season opening window swim season closing window

The bar compresses Phoenix's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the February 15–March 8 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 28. Wherever the today marker sits, the nearest color change is your next appointment.

The Phoenix pool calendar

February 22open by
November 28close by
21280°F+ days
92°Fwater peak

Opening — target February 22

Open by February 22 — a two-week head start on the March 8 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline November 28

The window opens November 18 once water leaves the algae zone; the model deadline is November 28, a week ahead of the December 25 freeze normal.

Full closing guide

Where the water sits today

SEASONAL VIEW

Estimated unheated pool water temp (site model, ±5°F). The live estimate loads in your browser from Open-Meteo air temperatures; in a typical year Phoenix water runs about 53°F at its winter floor and 92°F at its summer peak.

40 45 50 55 60 65 70 75 80 85 58 open 65 algae

Estimated water temperature by month

This is Phoenix'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.

40°50°60°70°80°90°100°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen Feb 22close Nov 2892°F peak53°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Phoenix Deer Valley Municipal Airport — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
54°56°60°67°74°83°91°92°90°80°68°56°

Warmest water typically June–October (peaking near 92°F); heaters and covers shift any month up.

Every station tells its own story: compare this curve with Peoria's pool season and Prescott Valley's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Arizona season index.

Phoenix pool season FAQ

When should I open my pool in Phoenix, AZ?

Open by February 22 — the model places Phoenix's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Phoenix opening guide has the 12-step sequence.

When should I close my pool in Phoenix?

Close by November 28: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Phoenix closing guide sequences the work backward from that date.

How long is the swim season in Phoenix?

Phoenix averages 212 days a year with normal highs of 80°F or better — right on the statewide median. The Arizona season index ranks all 20 covered cities by the same metric.

How warm does pool water get in Phoenix?

An unheated pool near Phoenix typically peaks around 92°F in high summer and bottoms out near 53°F in winter, spending roughly 5 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.

Data: NOAA 1991–2020 climate normals via Phoenix Deer Valley Municipal Airport (8.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.