Pool season · California
Pasadena Pool Season: the Year on One Bar
Last updated: July 25, 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.
Pasadena, CA — 152 swim days a yearReading 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
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.
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.
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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 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.
Every station tells its own story: compare this curve with Palo Alto's pool season and Perris's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Pasadena pool season FAQ
When should I open my pool in Pasadena, CA?
Target March 7. That date backs off two weeks from the day Pasadena's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Pasadena opening guide.
When should I close my pool in Pasadena?
The closing deadline is November 29 — late enough that the water has cooled out of the algae zone, early enough to beat Pasadena's first-freeze normal by about a week. See the Pasadena closing guide for the winterizing steps.
How long is the swim season in Pasadena?
Pasadena averages 152 days a year with normal highs of 80°F or better — about 25 days earlier than the California median. The California season index ranks all 147 covered cities by the same metric.
How warm does pool water get in Pasadena?
An unheated pool near Pasadena typically peaks around 78°F in high summer and bottoms out near 56°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 Pasadena hits the closing window
Data: NOAA 1991–2020 climate normals via Pasadena (0.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.