Pool season · California
San Leandro Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one San Leandro 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.
San Leandro, CA — 0 swim days a yearThe bar compresses San Leandro's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the May 8–May 29 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 28. Wherever the today marker sits, the nearest color change is your next appointment.
The San Leandro pool calendar
Opening — target May 15
Target May 15; the practical window runs May 8–May 29, and the 7-day mean crosses the 61°F threshold around May 29. Cold-water starts are the cheap ones.
Closing — deadline October 28
The window opens October 18 once water leaves the algae zone; the model deadline is October 28, a week ahead of the December 23 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on San Leandro's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 50° | 51° | 54° | 56° | 59° | 62° | 64° | 64° | 65° | 63° | 58° | 52° |
The curve peaks near 65°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with San Jose's pool season and San Marcos's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
San Leandro pool season FAQ
When should I open my pool in San Leandro, CA?
Open by May 15 — the model places San Leandro's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The San Leandro opening guide has the 12-step sequence.
When should I close my pool in San Leandro?
Close by October 28: cool water keeps its winter chemistry, but freeze damage is the hard stop. The San Leandro closing guide sequences the work backward from that date.
How long is the swim season in San Leandro?
San Leandro averages 0 days a year with normal highs of 80°F or better — about 44 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 San Leandro?
An unheated pool near San Leandro typically peaks around 65°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.
Email me when San Leandro hits the closing window
Data: NOAA 1991–2020 climate normals via Oakland Metro International Airport (3.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.