Pool season · South Dakota
Rapid City Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
This is the one-page view of Rapid City's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.
The bar compresses Rapid City's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the May 13–June 3 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends September 29. Wherever the today marker sits, the nearest color change is your next appointment.
The Rapid City pool calendar
Opening — target May 20
Target May 20; the practical window runs May 13–June 3, and the 7-day mean crosses the 61°F threshold around June 3. Cold-water starts are the cheap ones.
Closing — deadline September 29
Hold the cover until September 19, then winterize by September 29, a week ahead of the October 8 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Rapid City'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 27° | 26° | 32° | 41° | 50° | 61° | 70° | 73° | 68° | 55° | 42° | 32° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Rapid City hits the closing window
Data: NOAA 1991–2020 climate normals via Rapid City Wfo (0.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.