Pool season · Wisconsin
Eau Claire Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Eau Claire'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.
Eau Claire, WI — 52 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Eau Claire's swim season; the hollow teal run before it (April 30 to May 21) is when to open; the hollow amber run after is when to close, with September 27 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Eau Claire pool calendar
Opening — target May 7
Target May 7; the practical window runs April 30–May 21, and the 7-day mean crosses the 61°F threshold around May 21. Cold-water starts are the cheap ones.
Closing — deadline September 27
Hold the cover until September 17, then winterize by September 27, 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 Eau Claire'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 18° | 17° | 27° | 40° | 53° | 65° | 71° | 72° | 66° | 56° | 41° | 28° |
The curve peaks near 73°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Appleton's pool season and Green Bay's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Wisconsin season index.
Eau Claire pool season FAQ
When should I open my pool in Eau Claire, WI?
Open by May 7 — the model places Eau Claire's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Eau Claire opening guide has the 12-step sequence.
When should I close my pool in Eau Claire?
Close by September 27: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Eau Claire closing guide sequences the work backward from that date.
How long is the swim season in Eau Claire?
Eau Claire averages 52 days a year with normal highs of 80°F or better — about 6 days earlier than the Wisconsin median. The Wisconsin season index ranks all 11 covered cities by the same metric.
How warm does pool water get in Eau Claire?
An unheated pool near Eau Claire typically peaks around 73°F in high summer and bottoms out near 16°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 Eau Claire hits the closing window
Data: NOAA 1991–2020 climate normals via Eau Claire 3sw (2.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.