Pool season · California
Gilroy Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Gilroy'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.
Gilroy, CA — 134 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Gilroy's swim season; the hollow teal run before it (April 12 to May 3) is when to open; the hollow amber run after is when to close, with November 5 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Gilroy pool calendar
Opening — target April 19
Target April 19; the practical window runs April 12–May 3, and the 7-day mean crosses the 61°F threshold around May 3. Cold-water starts are the cheap ones.
Closing — deadline November 5
Hold the cover until October 26, then winterize by November 5, a week ahead of the November 27 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Gilroy'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 49° | 51° | 54° | 57° | 61° | 65° | 69° | 71° | 70° | 66° | 59° | 51° |
The curve peaks near 71°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Garden Grove's pool season and Glendale's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Gilroy pool season FAQ
When should I open my pool in Gilroy, CA?
Target April 19. That date backs off two weeks from the day Gilroy's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Gilroy opening guide.
When should I close my pool in Gilroy?
The closing deadline is November 5 — late enough that the water has cooled out of the algae zone, early enough to beat Gilroy's first-freeze normal by about a week. See the Gilroy closing guide for the winterizing steps.
How long is the swim season in Gilroy?
Gilroy averages 134 days a year with normal highs of 80°F or better — about 18 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 Gilroy?
An unheated pool near Gilroy typically peaks around 71°F in high summer and bottoms out near 48°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 Gilroy hits the closing window
Data: NOAA 1991–2020 climate normals via Gilroy (1.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.