Pool season · California
Downey Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Downey's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.
Downey, CA — 89 swim days a yearEach dot on the bar is one week of Downey's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (March 9–March 30), solid teal is swim season, and hollow amber is the closing window ending November 29. The black marker is today — its position against the colors is the entire executive summary.
The Downey pool calendar
Opening — target March 16
Target March 16; the practical window runs March 9–March 30, and the 7-day mean crosses the 61°F threshold around March 30. Cold-water starts are the cheap ones.
Closing — deadline November 29
Hold the cover until November 19, then winterize by November 29, a week ahead of the January 2 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Downey'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 57° | 57° | 59° | 61° | 64° | 67° | 71° | 74° | 74° | 71° | 65° | 58° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Davis's pool season and Dublin's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Downey pool season FAQ
When should I open my pool in Downey, CA?
Target March 16. That date backs off two weeks from the day Downey's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Downey opening guide.
When should I close my pool in Downey?
The closing deadline is November 29 — late enough that the water has cooled out of the algae zone, early enough to beat Downey's first-freeze normal by about a week. See the Downey closing guide for the winterizing steps.
How long is the swim season in Downey?
Downey averages 89 days a year with normal highs of 80°F or better — about 16 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 Downey?
An unheated pool near Downey typically peaks around 74°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 Downey hits the closing window
Data: NOAA 1991–2020 climate normals via Long Beach Daugherty Field (8.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.