Pool season · California
Napa Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Napa 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.
The bar compresses Napa's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 11–May 2 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 5. Wherever the today marker sits, the nearest color change is your next appointment.
The Napa pool calendar
Opening — target April 18
Open by April 18 — a two-week head start on the May 2 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline November 5
Hold the cover until October 26, then winterize by November 5, a week ahead of the December 4 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Napa's typical-year water curve: the same EWMA model as the live widget, run on the 1991–2020 normals instead of this week's weather.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 49° | 51° | 54° | 57° | 61° | 66° | 69° | 69° | 70° | 67° | 59° | 51° |
The curve peaks near 70°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Napa hits the closing window
Data: NOAA 1991–2020 climate normals via Napa State Hospital (2.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.