PoolWindow

Pool season · California

Pasadena Pool Season: the Year on One Bar

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

One bar, one year, one Pasadena pool. The season bar below draws everything the model knows — opening window, prime season, closing window — against today's date, with the working details one click away on the opening and closing pages.

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

off-season opening window swim season closing window

Reading it takes ten seconds: 52 dots, one per week. Solid teal is Pasadena's swim season; the hollow teal run before it (February 28 to March 21) is when to open; the hollow amber run after is when to close, with November 29 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.

The Pasadena pool calendar

March 7open by
November 29close by
15280°F+ days
78°Fwater peak

Opening — target March 7

Target March 7; the practical window runs February 28–March 21, and the 7-day mean crosses the 61°F threshold around March 21. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline November 29

The window opens November 19 once water leaves the algae zone; the model deadline is November 29, a week ahead of the January 7 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 Pasadena water runs about 56°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

This is Pasadena'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 Pasadena — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
56°57°59°62°65°68°74°77°77°73°66°58°

The curve peaks near 78°F — comfortable-water months here usually involve a heater or a solar cover.

Data: NOAA 1991–2020 climate normals via Pasadena (0.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.