Pool season · California
Rocklin Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Rocklin'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.
Rocklin, CA — 135 swim days a yearEach dot on the bar is one week of Rocklin'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 13–May 4), solid teal is swim season, and hollow amber is the closing window ending November 4. The black marker is today — its position against the colors is the entire executive summary.
The Rocklin pool calendar
Opening — target April 20
Target April 20; the practical window runs April 13–May 4, and the 7-day mean crosses the 61°F threshold around May 4. Cold-water starts are the cheap ones.
Closing — deadline November 4
The window opens October 25 once water leaves the algae zone; the model deadline is November 4, a week ahead of the December 5 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Rocklin'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 46° | 48° | 51° | 54° | 61° | 68° | 76° | 78° | 76° | 69° | 58° | 49° |
Warmest water typically August–August (peaking near 79°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Riverside's pool season and Roseville's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Rocklin pool season FAQ
When should I open my pool in Rocklin, CA?
The site model recommends opening by April 20 — about two weeks before Rocklin'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 Rocklin opening guide.
When should I close my pool in Rocklin?
Winterize by November 4. The model holds the deadline a week ahead of Rocklin's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Rocklin closing guide.
How long is the swim season in Rocklin?
Rocklin averages 135 days a year with normal highs of 80°F or better — about 19 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 Rocklin?
An unheated pool near Rocklin typically peaks around 79°F in high summer and bottoms out near 46°F in winter, spending roughly 1 month at or above the 78°F comfort line most swimmers prefer. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Rocklin hits the closing window
Data: NOAA 1991–2020 climate normals via Auburn (11.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.