Pool season · Washington
Olympia Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Olympia's whole pool calendar, condensed: when the water warms, when it cools, and where today falls between those edges. Use the opening guide and closing guide for the step-by-step work; keep this page for the dates.
Olympia, WA — 0 swim days a yearThe bar compresses Olympia's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the June 7–June 28 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends September 18. Wherever the today marker sits, the nearest color change is your next appointment.
The Olympia pool calendar
Opening — target June 14
Target June 14; the practical window runs June 7–June 28, and the 7-day mean crosses the 61°F threshold around June 28. Cold-water starts are the cheap ones.
Closing — deadline September 18
Hold the cover until September 8, then winterize by September 18, a week ahead of the October 14 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Olympia'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 39° | 40° | 42° | 46° | 52° | 57° | 62° | 65° | 62° | 55° | 46° | 40° |
The curve peaks near 65°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Marysville's pool season and Pasco's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Washington season index.
Olympia pool season FAQ
When should I open my pool in Olympia, WA?
Target June 14. That date backs off two weeks from the day Olympia's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Olympia opening guide.
When should I close my pool in Olympia?
The closing deadline is September 18 — late enough that the water has cooled out of the algae zone, early enough to beat Olympia's first-freeze normal by about a week. See the Olympia closing guide for the winterizing steps.
How long is the swim season in Olympia?
Olympia averages 0 days a year with normal highs of 80°F or better — about 21 days later than the Washington median. The Washington season index ranks all 21 covered cities by the same metric.
How warm does pool water get in Olympia?
An unheated pool near Olympia typically peaks around 65°F in high summer and bottoms out near 39°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Olympia hits the closing window
Data: NOAA 1991–2020 climate normals via Olympia Airport (4.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.