PoolWindow

Pool season · California

Mountain View Pool Season: the Year on One Bar

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

One bar, one year, one Mountain View 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 climateMountain View, CA — 0 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 Mountain View's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 16–May 7 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 7. Wherever the today marker sits, the nearest color change is your next appointment.

The Mountain View pool calendar

April 23open by
November 7close by
080°F+ days
68°Fwater peak

Opening — target April 23

Target April 23; the practical window runs April 16–May 7, and the 7-day mean crosses the 61°F threshold around May 7. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline November 7

The window opens October 28 once water leaves the algae zone; the model deadline is November 7, a week ahead of the December 23 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 Mountain View water runs about 50°F at its winter floor and 68°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 Mountain View'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 23close Nov 768°F peak50°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Moffett Federal Airfield — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
50°52°55°57°60°64°67°68°68°66°60°52°

The curve peaks near 68°F — comfortable-water months here usually involve a heater or a solar cover.

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

Mountain View pool season FAQ

When should I open my pool in Mountain View, CA?

Target April 23. That date backs off two weeks from the day Mountain View's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Mountain View opening guide.

When should I close my pool in Mountain View?

The closing deadline is November 7 — late enough that the water has cooled out of the algae zone, early enough to beat Mountain View's first-freeze normal by about a week. See the Mountain View closing guide for the winterizing steps.

How long is the swim season in Mountain View?

Mountain View averages 0 days a year with normal highs of 80°F or better — about 22 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 Mountain View?

An unheated pool near Mountain View typically peaks around 68°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 Moffett Federal Airfield (1.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.