PoolWindow

Pool season · California

Brentwood Pool Season: the Year on One Bar

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

This is the one-page view of Brentwood's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.

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 Brentwood's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the March 27–April 17 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 10. Wherever the today marker sits, the nearest color change is your next appointment.

The Brentwood pool calendar

April 3open by
November 10close by
14280°F+ days
76°Fwater peak

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.

Full opening guide

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.

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 Brentwood water runs about 47°F at its winter floor and 76°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 Brentwood'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 Antioch Pumping Plt #3 — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
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.

Data: NOAA 1991–2020 climate normals via Antioch Pumping Plt #3 (3.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.