Pool season · California
Alameda Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Alameda's whole pool calendar, condensed: when the water warms, when it cools, and where today falls between those edges. Use the opening guide and closing guide for the step-by-step work; keep this page for the dates.
Alameda, CA — 0 swim days a yearEach dot on the bar is one week of Alameda'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 29–May 20), solid teal is swim season, and hollow amber is the closing window ending November 11. The black marker is today — its position against the colors is the entire executive summary.
The Alameda pool calendar
Opening — target May 6
Open by May 6 — a two-week head start on the May 20 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 11
Hold the cover until November 1, then winterize by November 11, a week ahead of the December 23 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Alameda'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° | 54° | 56° | 58° | 60° | 62° | 64° | 65° | 66° | 65° | 61° | 54° |
The curve peaks near 66°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Yuba City's pool season and Alhambra's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Alameda pool season FAQ
When should I open my pool in Alameda, CA?
Target May 6. That date backs off two weeks from the day Alameda's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Alameda opening guide.
When should I close my pool in Alameda?
The closing deadline is November 11 — late enough that the water has cooled out of the algae zone, early enough to beat Alameda's first-freeze normal by about a week. See the Alameda closing guide for the winterizing steps.
How long is the swim season in Alameda?
Alameda averages 0 days a year with normal highs of 80°F or better — about 35 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 Alameda?
An unheated pool near Alameda typically peaks around 66°F in high summer and bottoms out near 52°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 Alameda hits the closing window
Data: NOAA 1991–2020 climate normals via Oakland Museum (2.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.