PoolWindow

Pool season · California

Hayward Pool Season: the Year on One Bar

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

Hayward'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 Hayward's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 28–May 19 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 7. Wherever the today marker sits, the nearest color change is your next appointment.

The Hayward pool calendar

May 5open by
November 7close by
080°F+ days
68°Fwater peak

Opening — target May 5

Open by May 5 — a two-week head start on the May 19 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline November 7

The window opens October 28 once water leaves the algae zone; the model deadline is November 7, a week ahead of the December 25 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 Hayward water runs about 51°F at its winter floor and 68°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 Hayward'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 Hayward Air Terminal — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
51°52°55°57°60°63°66°67°68°66°60°53°

The curve peaks near 68°F — comfortable-water months here usually involve a heater or a solar cover.

Data: NOAA 1991–2020 climate normals via Hayward Air Terminal (2.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.