Pool season · California
Santa Ana Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Santa Ana'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.
Santa Ana, CA — 105 swim days a yearEach dot on the bar is one week of Santa Ana's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (February 16–March 9), solid teal is swim season, and hollow amber is the closing window ending December 4. The black marker is today — its position against the colors is the entire executive summary.
The Santa Ana pool calendar
Opening — target February 23
Open by February 23 — a two-week head start on the March 9 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline December 4
The window opens November 24 once water leaves the algae zone; the model deadline is December 4, a week ahead of the December 25 freeze normal.
Estimated water temperature by month
This is Santa Ana'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 59° | 59° | 60° | 63° | 65° | 68° | 72° | 74° | 75° | 72° | 67° | 60° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with San Ramon's pool season and Santa Barbara's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Santa Ana pool season FAQ
When should I open my pool in Santa Ana, CA?
Open by February 23 — the model places Santa Ana's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Santa Ana opening guide has the 12-step sequence.
When should I close my pool in Santa Ana?
Close by December 4: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Santa Ana closing guide sequences the work backward from that date.
How long is the swim season in Santa Ana?
Santa Ana averages 105 days a year with normal highs of 80°F or better — about 37 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 Santa Ana?
An unheated pool near Santa Ana typically peaks around 75°F in high summer and bottoms out near 58°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 Santa Ana hits the closing window
Data: NOAA 1991–2020 climate normals via Santa Ana Fire Station (1.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.