PoolWindow

Pool season · California

Fairfield Pool Season: the Year on One Bar

Last updated: July 15, 2026 · dates · water temp

Fairfield'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 Fairfield's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 4–April 25 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 Fairfield pool calendar

April 11open by
November 9close by
13980°F+ days
74°Fwater peak

Opening — target April 11

Target April 11; the practical window runs April 4–April 25, and the 7-day mean crosses the 61°F threshold around April 25. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline November 9

Hold the cover until October 30, then winterize by November 9, a week ahead of the December 14 freeze normal. Late and cold beats early and warm.

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 Fairfield water runs about 48°F at its winter floor and 74°F at its summer peak.

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

Estimated water temperature by month

This is Fairfield'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.

Site-model seasonal water estimates for an unheated in-ground pool near Fairfield — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
48°50°54°58°62°68°73°74°73°69°60°51°

The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.

Data: NOAA 1991–2020 climate normals via Fairfield (2.1 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.