Pool season · California
Redwood City Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Redwood City'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.
Redwood City, CA — 80 swim days a yearEach dot on the bar is one week of Redwood City'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 21–May 12), solid teal is swim season, and hollow amber is the closing window ending November 1. The black marker is today — its position against the colors is the entire executive summary.
The Redwood City pool calendar
Opening — target April 28
Open by April 28 — a two-week head start on the May 12 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 1
The window opens October 22 once water leaves the algae zone; the model deadline is November 1, a week ahead of the December 12 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Redwood City'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° | 56° | 60° | 64° | 68° | 69° | 68° | 65° | 58° | 51° |
The curve peaks near 69°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Redondo Beach's pool season and Rialto's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Redwood City pool season FAQ
When should I open my pool in Redwood City, CA?
The site model recommends opening by April 28 — about two weeks before Redwood City'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 Redwood City opening guide.
When should I close my pool in Redwood City?
Winterize by November 1. The model holds the deadline a week ahead of Redwood City's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Redwood City closing guide.
How long is the swim season in Redwood City?
Redwood City averages 80 days a year with normal highs of 80°F or better — about 27 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 Redwood City?
An unheated pool near Redwood City typically peaks around 69°F in high summer and bottoms out near 49°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 Redwood City hits the closing window
Data: NOAA 1991–2020 climate normals via Redwood City (1.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.