Pool season · Minnesota
Rochester Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Rochester'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.
Rochester, MN — 28 swim days a yearThe bar compresses Rochester's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the May 4–May 25 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends September 26. Wherever the today marker sits, the nearest color change is your next appointment.
The Rochester pool calendar
Opening — target May 11
Target May 11; the practical window runs May 4–May 25, and the 7-day mean crosses the 61°F threshold around May 25. Cold-water starts are the cheap ones.
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 Rochester'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 17° | 16° | 26° | 40° | 52° | 64° | 70° | 70° | 65° | 55° | 40° | 27° |
The curve peaks near 71°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Plymouth's pool season and St. Cloud's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Minnesota season index.
Rochester pool season FAQ
When should I open my pool in Rochester, MN?
Target May 11. That date backs off two weeks from the day Rochester's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Rochester opening guide.
When should I close my pool in Rochester?
The closing deadline is September 26 — late enough that the water has cooled out of the algae zone, early enough to beat Rochester's first-freeze normal by about a week. See the Rochester closing guide for the winterizing steps.
How long is the swim season in Rochester?
Rochester averages 28 days a year with normal highs of 80°F or better — right on the statewide median. The Minnesota season index ranks all 10 covered cities by the same metric.
How warm does pool water get in Rochester?
An unheated pool near Rochester typically peaks around 71°F in high summer and bottoms out near 15°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 Rochester hits the closing window
Data: NOAA 1991–2020 climate normals via Rochester International Airport (7.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.