Pool season · California
Santa Rosa Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Santa Rosa'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.
Santa Rosa, CA — 123 swim days a yearEach dot on the bar is one week of Santa Rosa's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (April 25–May 16), solid teal is swim season, and hollow amber is the closing window ending November 5. The black marker is today — its position against the colors is the entire executive summary.
The Santa Rosa pool calendar
Opening — target May 2
Target May 2; the practical window runs April 25–May 16, and the 7-day mean crosses the 61°F threshold around May 16. 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 December 1 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Santa Rosa'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 48° | 50° | 53° | 56° | 59° | 64° | 67° | 67° | 68° | 66° | 59° | 51° |
The curve peaks near 68°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Santa Monica's pool season and Seaside's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Santa Rosa pool season FAQ
When should I open my pool in Santa Rosa, CA?
The site model recommends opening by May 2 — about two weeks before Santa Rosa'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 Santa Rosa opening guide.
When should I close my pool in Santa Rosa?
Winterize by November 5. The model holds the deadline a week ahead of Santa Rosa's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Santa Rosa closing guide.
How long is the swim season in Santa Rosa?
Santa Rosa averages 123 days a year with normal highs of 80°F or better — about 31 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 Santa Rosa?
An unheated pool near Santa Rosa typically peaks around 68°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 Santa Rosa hits the closing window
Data: NOAA 1991–2020 climate normals via Santa Rosa (0.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.