Pool season · California
Fontana Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Fontana pool. The season bar below draws everything the model knows — opening window, prime season, closing window — against today's date, with the working details one click away on the opening and closing pages.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Fontana's swim season; the hollow teal run before it (March 4 to March 25) is when to open; the hollow amber run after is when to close, with November 28 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Fontana pool calendar
Opening — target March 11
Open by March 11 — a two-week head start on the March 25 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 December 30 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Fontana'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° | 56° | 59° | 62° | 66° | 70° | 77° | 80° | 80° | 74° | 66° | 58° |
Warmest water typically August–September (peaking near 80°F); heaters and covers shift any month up.
Email me when Fontana hits the closing window
Data: NOAA 1991–2020 climate normals via Ontario International Airport (8.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.