Pool season · California
Upland Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Upland 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.
Upland, CA — 164 swim days a yearThe bar compresses Upland's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the March 4–March 25 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 28. Wherever the today marker sits, the nearest color change is your next appointment.
The Upland pool calendar
Opening — target March 11
Target March 11; the practical window runs March 4–March 25, and the 7-day mean crosses the 61°F threshold around March 25. Cold-water starts are the cheap ones.
Closing — deadline November 28
Hold the cover until November 18, then winterize by November 28, a week ahead of the December 30 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Upland'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.
Every station tells its own story: compare this curve with Union City's pool season and Vacaville's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Upland pool season FAQ
When should I open my pool in Upland, CA?
Open by March 11 — the model places Upland's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Upland opening guide has the 12-step sequence.
When should I close my pool in Upland?
Close by November 28: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Upland closing guide sequences the work backward from that date.
How long is the swim season in Upland?
Upland averages 164 days a year with normal highs of 80°F or better — about 21 days earlier than the California median. The California season index ranks all 147 covered cities by the same metric.
How warm does pool water get in Upland?
An unheated pool near Upland typically peaks around 80°F in high summer and bottoms out near 55°F in winter, spending roughly 2 months 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 Upland hits the closing window
Data: NOAA 1991–2020 climate normals via Ontario International Airport (5.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.