Pool season · California
Seaside Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Seaside'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.
Seaside, CA — 0 swim days a yearThe bar compresses Seaside's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the June 10–July 1 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 20. Wherever the today marker sits, the nearest color change is your next appointment.
The Seaside pool calendar
Opening — target June 17
Target June 17; the practical window runs June 10–July 1, and the 7-day mean crosses the 61°F threshold around July 1. Cold-water starts are the cheap ones.
Closing — deadline October 20
The window opens October 10 once water leaves the algae zone; the model deadline is October 20, a week ahead of the December 23 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Seaside's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 52° | 53° | 54° | 55° | 57° | 59° | 61° | 62° | 63° | 62° | 58° | 53° |
The curve peaks near 63°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Santa Rosa's pool season and Simi Valley's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Seaside pool season FAQ
When should I open my pool in Seaside, CA?
The site model recommends opening by June 17 — about two weeks before Seaside's 7-day mean temperature crosses 61°F, while the water is still too cold for algae. The step-by-step sequence is in the Seaside opening guide.
When should I close my pool in Seaside?
Winterize by October 20. The model holds the deadline a week ahead of Seaside's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Seaside closing guide.
How long is the swim season in Seaside?
Seaside averages 0 days a year with normal highs of 80°F or better — about 77 days later than the California median. The California season index ranks all 147 covered cities by the same metric.
How warm does pool water get in Seaside?
An unheated pool near Seaside typically peaks around 63°F in high summer and bottoms out near 52°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Seaside hits the closing window
Data: NOAA 1991–2020 climate normals via Monterey Peninsul Airport (2.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.