The temperatures in South Dakota in September are comfortable with low of 12°C and and high up to 24°C.
You can expect about 3 to 8 days of rain in South Dakota during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in South Dakota in September 2025.
If you’re planning to visit South Dakota in the near future, we highly recommend that you review the 14 day weather forecast for South Dakota before you arrive.