PoolWindow

Pool season · California

Lake Forest Pool Season: the Year on One Bar

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

One bar, one year, one Lake Forest 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

Each dot on the bar is one week of Lake Forest's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (February 18–March 11), solid teal is swim season, and hollow amber is the closing window ending December 5. The black marker is today — its position against the colors is the entire executive summary.

The Lake Forest pool calendar

February 25open by
December 5close by
15780°F+ days
76°Fwater peak

Opening — target February 25

Open by February 25 — a two-week head start on the March 11 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline December 5

Hold the cover until November 25, then winterize by December 5, a week ahead of the December 25 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 Lake Forest water runs about 58°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

This is Lake Forest'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 Irvine Rch — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
58°59°60°63°66°69°73°76°76°73°68°60°

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 Irvine Rch (5.1 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.