Pool season · California
Rialto Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
Rialto'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.
Each dot on the bar is one week of Rialto'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 14–April 4), solid teal is swim season, and hollow amber is the closing window ending November 28. The black marker is today — its position against the colors is the entire executive summary.
The Rialto pool calendar
Opening — target March 21
Open by March 21 — a two-week head start on the April 4 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 28
The window opens November 18 once water leaves the algae zone; the model deadline is November 28, a week ahead of the January 2 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Rialto'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 56° | 57° | 58° | 61° | 65° | 70° | 76° | 80° | 79° | 72° | 65° | 58° |
Warmest water typically August–September (peaking near 80°F); heaters and covers shift any month up.
Email me when Rialto hits the closing window
Data: NOAA 1991–2020 climate normals via Riverside Citrus Experiment (10.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.