PoolWindow

Pool season · California

Milpitas Pool Season: the Year on One Bar

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

One bar, one year, one Milpitas pool. The season bar below draws everything the model knows — opening window, prime season, closing window — against today's date, with the working details one click away on the opening and closing pages.

Cool blue pool in a short-season northern climateMilpitas, CA — 94 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

Each dot on the bar is one week of Milpitas's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (April 12–May 3), solid teal is swim season, and hollow amber is the closing window ending November 8. The black marker is today — its position against the colors is the entire executive summary.

The Milpitas pool calendar

April 19open by
November 8close by
9480°F+ days
70°Fwater peak

Opening — target April 19

Open by April 19 — a two-week head start on the May 3 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline November 8

The window opens October 29 once water leaves the algae zone; the model deadline is November 8, a week ahead of the December 22 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 Milpitas water runs about 50°F at its winter floor and 70°F at its summer peak.

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

Estimated water temperature by month

Monthly averages of the site's water model run on Milpitas's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.

40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen Apr 19close Nov 870°F peak50°F floor
Site-model seasonal water estimates for an unheated in-ground pool near San Jose — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
50°52°55°57°61°66°69°70°70°67°60°52°

The curve peaks near 70°F — comfortable-water months here usually involve a heater or a solar cover.

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

Milpitas pool season FAQ

When should I open my pool in Milpitas, CA?

The site model recommends opening by April 19 — about two weeks before Milpitas's 7-day mean temperature crosses 61°F, while the water is still too cold for algae. The step-by-step sequence is in the Milpitas opening guide.

When should I close my pool in Milpitas?

Winterize by November 8. The model holds the deadline a week ahead of Milpitas's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Milpitas closing guide.

How long is the swim season in Milpitas?

Milpitas averages 94 days a year with normal highs of 80°F or better — about 18 days later than the California median. The California season index ranks all 147 covered cities by the same metric.

How warm does pool water get in Milpitas?

An unheated pool near Milpitas typically peaks around 70°F in high summer and bottoms out near 50°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. 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 San Jose (5.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.