Pool season · California
Hesperia Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
This is the one-page view of Hesperia'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.
The bar compresses Hesperia's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the March 30–April 20 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 9. Wherever the today marker sits, the nearest color change is your next appointment.
The Hesperia pool calendar
Opening — target April 6
Open by April 6 — a two-week head start on the April 20 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 9
Hold the cover until October 30, then winterize by November 9, a week ahead of the December 1 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Hesperia'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 48° | 49° | 53° | 58° | 64° | 72° | 79° | 81° | 79° | 71° | 60° | 50° |
Warmest water typically July–September (peaking near 81°F); heaters and covers shift any month up.
Email me when Hesperia hits the closing window
Data: NOAA 1991–2020 climate normals via Hesperia 2e (3.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.