PoolWindow

Pool season · California

Folsom Pool Season: the Year on One Bar

Last updated: July 15, 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.

J F M A M J J A S O N D today (build date)

off-season opening window swim season closing window

The 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

April 1open by
November 9close by
15680°F+ days
78°Fwater peak

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.

Full opening guide

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.

Full closing guide

Where the water sits today

SEASONAL VIEW

Estimated unheated pool water temp (site model, ±5°F). The live estimate loads in your browser from Open-Meteo air temperatures; in a typical year Folsom water runs about 48°F at its winter floor and 78°F at its summer peak.

40 45 50 55 60 65 70 75 80 85 58 open 65 algae

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.

Site-model seasonal water estimates for an unheated in-ground pool near Sacramento 5 ESE — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
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.

Data: NOAA 1991–2020 climate normals via Sacramento 5 ESE (16.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.