Pool season · California
Alhambra Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Alhambra'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.
Alhambra, CA — 130 swim days a yearThe bar compresses Alhambra's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the February 25–March 18 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 30. Wherever the today marker sits, the nearest color change is your next appointment.
The Alhambra pool calendar
Opening — target March 4
Open by March 4 — a two-week head start on the March 18 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 30
Hold the cover until November 20, then winterize by November 30, a week ahead of the January 2 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Alhambra'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 57° | 57° | 59° | 62° | 65° | 69° | 74° | 76° | 77° | 72° | 66° | 58° |
The curve peaks near 77°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Alameda's pool season and Anaheim's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Alhambra pool season FAQ
When should I open my pool in Alhambra, CA?
Open by March 4 — the model places Alhambra's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Alhambra opening guide has the 12-step sequence.
When should I close my pool in Alhambra?
Close by November 30: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Alhambra closing guide sequences the work backward from that date.
How long is the swim season in Alhambra?
Alhambra averages 130 days a year with normal highs of 80°F or better — about 28 days earlier than the California median. The California season index ranks all 147 covered cities by the same metric.
How warm does pool water get in Alhambra?
An unheated pool near Alhambra typically peaks around 77°F in high summer and bottoms out near 56°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 Alhambra hits the closing window
Data: NOAA 1991–2020 climate normals via San Gabriel Fire Dept (2.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.