Pool season · Washington
Renton Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Renton 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.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Renton's swim season; the hollow teal run before it (May 17 to June 7) is when to open; the hollow amber run after is when to close, with October 1 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Renton pool calendar
Opening — target May 24
Target May 24; the practical window runs May 17–June 7, and the 7-day mean crosses the 61°F threshold around June 7. Cold-water starts are the cheap ones.
Closing — deadline October 1
The window opens September 21 once water leaves the algae zone; the model deadline is October 1, a week ahead of the November 16 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Renton'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 42° | 43° | 45° | 49° | 55° | 60° | 65° | 68° | 65° | 58° | 50° | 43° |
The curve peaks near 68°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Renton hits the closing window
Data: NOAA 1991–2020 climate normals via Renton Municipal Airport (1.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.