Pool season · California
Concord Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Concord'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.
Concord, CA — 135 swim days a yearEach dot on the bar is one week of Concord'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 1–April 22), solid teal is swim season, and hollow amber is the closing window ending November 9. The black marker is today — its position against the colors is the entire executive summary.
The Concord pool calendar
Opening — target April 8
Open by April 8 — a two-week head start on the April 22 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 9
The window opens October 30 once water leaves the algae zone; the model deadline is November 9, a week ahead of the December 14 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Concord'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 49° | 51° | 55° | 58° | 63° | 68° | 73° | 74° | 73° | 69° | 60° | 52° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Compton's pool season and Corona's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Concord pool season FAQ
When should I open my pool in Concord, CA?
Open by April 8 — the model places Concord's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Concord opening guide has the 12-step sequence.
When should I close my pool in Concord?
Close by November 9: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Concord closing guide sequences the work backward from that date.
How long is the swim season in Concord?
Concord averages 135 days a year with normal highs of 80°F or better — about 7 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 Concord?
An unheated pool near Concord typically peaks around 74°F in high summer and bottoms out near 49°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 Concord hits the closing window
Data: NOAA 1991–2020 climate normals via Concord Buchanan Field (3.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.