Pool season · California
Livermore Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
This is the one-page view of Livermore'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.
Each dot on the bar is one week of Livermore's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (April 12–May 3), solid teal is swim season, and hollow amber is the closing window ending November 3. The black marker is today — its position against the colors is the entire executive summary.
The Livermore pool calendar
Opening — target April 19
Target April 19; the practical window runs April 12–May 3, and the 7-day mean crosses the 61°F threshold around May 3. Cold-water starts are the cheap ones.
Closing — deadline November 3
Hold the cover until October 24, then winterize by November 3, a week ahead of the December 2 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Livermore'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 47° | 49° | 53° | 56° | 61° | 66° | 72° | 73° | 72° | 67° | 58° | 50° |
The curve peaks near 73°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Livermore hits the closing window
Data: NOAA 1991–2020 climate normals via Livermore (3.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.