September weather forecast
South Dakota, USA

September ushers in the full embrace of autumn in South Dakota, marked by cooler temperatures, transforming landscapes, and a shift in atmospheric conditions. Daytime temperatures predominantly range from 65°F (18.3°C) to 75°F (23.9°C), while the nights experience a more significant drop, settling between 45°F (7.2°C) and 55°F (12.8°C). The nip in the air becomes more pronounced as the month progresses.

The Black Hills, always distinct in their weather patterns, are among the first regions in the state to showcase the vibrant fall foliage. Temperatures here might be a tad cooler, especially during the evenings, adding to the allure of the autumn season.

Rainfall in September is relatively moderate, but the focus is on the decreasing thunderstorm activity. Instead, gentle rains and cooler winds become more frequent, painting a serene picture that is characteristic of the fall season.

September stands in stark contrast to the warmer months of July and August. The decrease in temperatures is noticeable, and the state starts preparing for the colder months ahead.

The transition from August to September in South Dakota is not just about temperatures but is a sensory experience. The colors of nature shift from verdant greens to a palette of reds, oranges, and yellows, and the aroma of the fall season fills the air. As the month nears its end, there is an anticipation of the crispness of October, with its even cooler temperatures and further deepening of the autumnal hues.

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• Sioux Falls - September »
  In Sioux Falls, South Dakota, in September, during 10.5 rainfall days, 1.89" (48mm) of precipitation is typically accumulated. In Sioux Falls the average relative humidity in September is 70%.
• Rapid City - September »
  The months with the lowest humidity in Rapid City are August and September, with an average relative humidity of 50%. In Rapid City in September, during 7.8 rainfall days, 0.94" (24mm) of precipitation is typically accumulated.
• Aberdeen - September »
  The months with the lowest humidity in Aberdeen are August and September, with an average relative humidity of 60%. Aberdeen's weather in September involves a mild decrease in the average high-temperature, moving down slightly from August's 83.1°F (28.4°C) to a still moderately hot 74.3°F (23.5°C).
• Brookings - September »
  In Brookings in September, it is raining for 10.9 days, with typically 1.65" (42mm) of accumulated precipitation. In Brookings snow does not fall in June through September.
• Watertown - September »
  The average relative humidity in September in Watertown is 68%. In September, in Watertown, South Dakota, the rain falls for 10.4 days.
• Mitchell - September »
  On the first day of September in Mitchell, South Dakota, sunrise is at 6:55 am and sunset at 8:08 pm. On the first day of September in Mitchell sunrise is at 6:55 am and sunset at 8:08 pm.
• Yankton - September »
  In Yankton during September, the rain falls for 11.6 days and regularly aggregates up to 1.81" (46mm) of precipitation. In Yankton, during September, the rain falls for 11.6 days and regularly aggregates up to 1.81" (46mm) of precipitation.
• Pierre - September »
  In Pierre during September, the rain falls for 8.9 days and regularly aggregates up to 0.67" (17mm) of precipitation. In September, the average relative humidity is 52%.
• Huron - September »
  The least humid month in Huron, South Dakota, is September, with an average relative humidity of 62%. In Huron snow does not fall in May through September.
• Spearfish - September »
  In Spearfish in September, it is raining for 7.6 days, with typically 0.79" (20mm) of accumulated precipitation. In Spearfish, in September, it is raining for 7.6 days, with typically 0.79" (20mm) of accumulated precipitation.
• Vermillion - September »
  In the month of September, the temperature in Vermillion generally rests at an average low of 54.9°F (12.7°C). In Vermillion the average sunshine duration in September is 8.9h.
• Brandon - September »
  September in Brandon indicates a minor shift in the average high-temperature, from August's 80.8°F (27.1°C) to a still moderately hot 74.1°F (23.4°C). In Brandon, in September, during 10.8 rainfall days, 1.93" (49mm) of precipitation is typically accumulated.