Pool season · Washington
Pasco Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Pasco 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.
Pasco, WA — 107 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Pasco's swim season; the hollow teal run before it (April 23 to May 14) is when to open; the hollow amber run after is when to close, with October 4 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Pasco pool calendar
Opening — target April 30
Target April 30; the practical window runs April 23–May 14, and the 7-day mean crosses the 61°F threshold around May 14. Cold-water starts are the cheap ones.
Closing — deadline October 4
Hold the cover until September 24, then winterize by October 4, a week ahead of the October 11 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Pasco'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 34° | 36° | 42° | 50° | 57° | 65° | 72° | 75° | 69° | 58° | 46° | 37° |
The curve peaks near 76°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Olympia's pool season and Redmond's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Washington season index.
Pasco pool season FAQ
When should I open my pool in Pasco, WA?
The site model recommends opening by April 30 — about two weeks before Pasco'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 Pasco opening guide.
When should I close my pool in Pasco?
Winterize by October 4. The model holds the deadline a week ahead of Pasco's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Pasco closing guide.
How long is the swim season in Pasco?
Pasco averages 107 days a year with normal highs of 80°F or better — about 24 days earlier than the Washington median. The Washington season index ranks all 21 covered cities by the same metric.
How warm does pool water get in Pasco?
An unheated pool near Pasco typically peaks around 76°F in high summer and bottoms out near 34°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 Pasco hits the closing window
Data: NOAA 1991–2020 climate normals via Pasco Tri Cities Airport (1.3 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.