Pool season · South Dakota
Sioux Falls Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Sioux Falls 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.
Sioux Falls, SD — 73 swim days a yearEach dot on the bar is one week of Sioux Falls's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (April 29–May 20), solid teal is swim season, and hollow amber is the closing window ending October 2. The black marker is today — its position against the colors is the entire executive summary.
The Sioux Falls pool calendar
Opening — target May 6
Open by May 6 — a two-week head start on the May 20 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 2
Hold the cover until September 22, then winterize by October 2, a week ahead of the October 13 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Sioux Falls'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 18° | 18° | 27° | 41° | 53° | 66° | 73° | 74° | 68° | 57° | 41° | 27° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Rapid City's pool season or jump back to the South Dakota season index to see the statewide spread.
Sioux Falls pool season FAQ
When should I open my pool in Sioux Falls, SD?
Target May 6. That date backs off two weeks from the day Sioux Falls's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Sioux Falls opening guide.
When should I close my pool in Sioux Falls?
The closing deadline is October 2 — late enough that the water has cooled out of the algae zone, early enough to beat Sioux Falls's first-freeze normal by about a week. See the Sioux Falls closing guide for the winterizing steps.
How long is the swim season in Sioux Falls?
Sioux Falls averages 73 days a year with normal highs of 80°F or better — about 14 days earlier than the South Dakota median. The South Dakota season index ranks all 2 covered cities by the same metric.
How warm does pool water get in Sioux Falls?
An unheated pool near Sioux Falls typically peaks around 74°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 Sioux Falls hits the closing window
Data: NOAA 1991–2020 climate normals via Sioux Falls Wfo Airport (3.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.