Pool season · Minnesota
Duluth Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Duluth 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 Duluth's swim season; the hollow teal run before it (June 5 to June 26) is when to open; the hollow amber run after is when to close, with September 19 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Duluth pool calendar
Opening — target June 12
Target June 12; the practical window runs June 5–June 26, and the 7-day mean crosses the 61°F threshold around June 26. Cold-water starts are the cheap ones.
Closing — deadline September 19
Hold the cover until September 9, then winterize by September 19, a week ahead of the October 12 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Duluth'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15° | 14° | 22° | 33° | 44° | 53° | 63° | 68° | 63° | 52° | 38° | 26° |
The curve peaks near 68°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Duluth hits the closing window
Data: NOAA 1991–2020 climate normals via Duluth Harbor Station (2.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.