South Dakota Pool Season: Opening & Closing Dates by City

Local dates for every featured South Dakota city — when the water warms up, when it cools off, and how long the season actually lasts.

City Opening window Closing window Season
Sioux Falls May 24 – Jun 10 Aug 30 – Sep 19 ≈ 101 days
Rapid City Jun 5 – Jun 25 Aug 27 – Sep 16 ≈ 85 days

Windows show the stretch when each city's daily average passes through the low-to-mid 60s°F (1991–2020 NOAA records, nearest station to each city). Click a city for its month-by-month table and full season notes.

Season geography

Across South Dakota's featured cities, typical openings spread from Jun 1 to Jun 14, closings from Sep 6 to Sep 11, and the unheated season runs 85–101 days depending on where you are. Elevation, coastal water, and urban heat all pull real dates around, which is exactly why a state-level answer isn't enough.

For your exact town, the pool season lookup takes a ZIP code. Opening day itself is a chemistry job — the dosing calculator turns your first test reading of the year into exact amounts.

South Dakota planning pages

When to open — South Dakota When to close — South Dakota All states →