Pool season · California
Porterville Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Porterville'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.
Porterville, CA — 171 swim days a yearThe bar compresses Porterville's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the March 15–April 5 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 11. Wherever the today marker sits, the nearest color change is your next appointment.
The Porterville pool calendar
Opening — target March 22
Open by March 22 — a two-week head start on the April 5 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 11
The window opens November 1 once water leaves the algae zone; the model deadline is November 11, a week ahead of the December 13 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Porterville'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° | 52° | 56° | 61° | 67° | 74° | 81° | 83° | 80° | 73° | 61° | 52° |
Warmest water typically July–September (peaking near 84°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Pomona's pool season and Rancho Cordova's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the California season index.
Porterville pool season FAQ
When should I open my pool in Porterville, CA?
The site model recommends opening by March 22 — about two weeks before Porterville'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 Porterville opening guide.
When should I close my pool in Porterville?
Winterize by November 11. The model holds the deadline a week ahead of Porterville's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Porterville closing guide.
How long is the swim season in Porterville?
Porterville averages 171 days a year with normal highs of 80°F or better — about 10 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 Porterville?
An unheated pool near Porterville typically peaks around 84°F in high summer and bottoms out near 48°F in winter, spending roughly 3 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 Porterville hits the closing window
Data: NOAA 1991–2020 climate normals via Porterville (0.8 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.