Pool season · Wisconsin
Appleton Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Appleton 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.
Appleton, WI — 45 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Appleton's swim season; the hollow teal run before it (May 7 to May 28) is when to open; the hollow amber run after is when to close, with September 26 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Appleton pool calendar
Opening — target May 14
Open by May 14 — a two-week head start on the May 28 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline September 26
The window opens September 16 once water leaves the algae zone; the model deadline is September 26, a week ahead of the October 6 freeze normal.
Estimated water temperature by month
This is Appleton'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 20° | 18° | 26° | 38° | 51° | 63° | 70° | 71° | 66° | 55° | 42° | 29° |
The curve peaks near 72°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Wausau's pool season and Eau Claire's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Wisconsin season index.
Appleton pool season FAQ
When should I open my pool in Appleton, WI?
The site model recommends opening by May 14 — about two weeks before Appleton'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 Appleton opening guide.
When should I close my pool in Appleton?
Winterize by September 26. The model holds the deadline a week ahead of Appleton's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Appleton closing guide.
How long is the swim season in Appleton?
Appleton averages 45 days a year with normal highs of 80°F or better — right on the statewide median. The Wisconsin season index ranks all 11 covered cities by the same metric.
How warm does pool water get in Appleton?
An unheated pool near Appleton typically peaks around 72°F in high summer and bottoms out near 17°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 Appleton hits the closing window
Data: NOAA 1991–2020 climate normals via Appleton (2.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.