Pool season · California
Folsom Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Folsom'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.
Folsom, CA — 156 swim days a yearThe bar compresses Folsom's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the March 25–April 15 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 9. Wherever the today marker sits, the nearest color change is your next appointment.
The Folsom pool calendar
Opening — target April 1
Target April 1; the practical window runs March 25–April 15, and the 7-day mean crosses the 61°F threshold around April 15. Cold-water starts are the cheap ones.
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 16 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Folsom'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 48° | 51° | 56° | 59° | 65° | 71° | 77° | 78° | 76° | 70° | 60° | 51° |
Warmest water typically August–August (peaking near 78°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Fairfield's pool season and Fontana's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Folsom pool season FAQ
When should I open my pool in Folsom, CA?
The site model recommends opening by April 1 — about two weeks before Folsom's 7-day mean temperature crosses 61°F, while the water is still too cold for algae. The step-by-step sequence is in the Folsom opening guide.
When should I close my pool in Folsom?
Winterize by November 9. The model holds the deadline a week ahead of Folsom's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Folsom closing guide.
How long is the swim season in Folsom?
Folsom averages 156 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 Folsom?
An unheated pool near Folsom typically peaks around 78°F in high summer and bottoms out near 48°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 Folsom hits the closing window
Data: NOAA 1991–2020 climate normals via Sacramento 5 ESE (16.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.