Pool season · California
Antioch Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Antioch'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.
Antioch, CA — 142 swim days a yearEach dot on the bar is one week of Antioch's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (March 27–April 17), solid teal is swim season, and hollow amber is the closing window ending November 10. The black marker is today — its position against the colors is the entire executive summary.
The Antioch pool calendar
Opening — target April 3
Target April 3; the practical window runs March 27–April 17, and the 7-day mean crosses the 61°F threshold around April 17. Cold-water starts are the cheap ones.
Closing — deadline November 10
Hold the cover until October 31, then winterize by November 10, a week ahead of the December 19 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Antioch'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 47° | 50° | 55° | 59° | 64° | 70° | 75° | 76° | 74° | 70° | 60° | 51° |
The curve peaks near 76°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Anaheim's pool season and Apple Valley's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Antioch pool season FAQ
When should I open my pool in Antioch, CA?
Open by April 3 — the model places Antioch's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Antioch opening guide has the 12-step sequence.
When should I close my pool in Antioch?
Close by November 10: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Antioch closing guide sequences the work backward from that date.
How long is the swim season in Antioch?
Antioch averages 142 days a year with normal highs of 80°F or better — right on the statewide median. The California season index ranks all 147 covered cities by the same metric.
How warm does pool water get in Antioch?
An unheated pool near Antioch typically peaks around 76°F in high summer and bottoms out near 47°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 Antioch hits the closing window
Data: NOAA 1991–2020 climate normals via Antioch Pumping Plt #3 (2.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.