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 snow does not fall in June through September. In Sioux Falls, South Dakota, during September, the rain falls for 10.5 days and regularly aggregates up to 1.89" (48mm) of precipitation.
• Rapid City - September »
  On the first day of September in Rapid City, South Dakota, sunrise is at 6:17 am and sunset at 7:28 pm. September is the first month it typically snows in Rapid City, South Dakota.
• Aberdeen - September »
  In Aberdeen, South Dakota, snow does not fall in June through September. In September, in Aberdeen the rain falls for 8.9 days.
• Brookings - September »
  In Brookings, during September, the rain falls for 10.9 days and regularly aggregates up to 1.65" (42mm) of precipitation. On the last day of September, in Brookings, sunrise is at 7:24 am and sunset at 7:09 pm CDT.
• Watertown - September »
  In Watertown snow does not fall in June through September. In Watertown, in September, during 10.4 rainfall days, 1.57" (40mm) of precipitation is typically accumulated.
• Mitchell - September »
  September and October, with an average relative humidity of 63%, are the least humid months in Mitchell, South Dakota. In Mitchell during September, the rain falls for 9.2 days and regularly aggregates up to 1.18" (30mm) of precipitation.
• Yankton - September »
  September in Yankton is a month of change, where summer transitions into fall. In Yankton the average relative humidity in September is 67%.
• Pierre - September »
  August and September, with an average relative humidity of 52%, are the least humid months in Pierre. In Pierre the average relative humidity in September is 52%.
• Huron - September »
  In Huron during September, the rain falls for 9.8 days and regularly aggregates up to 1.38" (35mm) of precipitation. With an average relative humidity of 62%, September is the least humid month in Huron, South Dakota.
• Spearfish - September »
  In Spearfish, in September, it is raining for 7.6 days, with typically 0.79" (20mm) of accumulated precipitation. Onset of September in Spearfish, South Dakota, witnesses a reduction in the average high-temperature, falling from a moderately hot 81.9°F (27.7°C) in August to a pleasant 72.5°F (22.5°C).
• Vermillion - September »
  On the first day of September in Vermillion, sunrise is at 6:53 am and sunset at 8:01 pm. Vermillion in September stands on the brink of transition, sliding gently from the remaining summer heat into the arms of Fall.
• Brandon - September »
  In September, in Brandon, South Dakota, the rain falls for 10.8 days. September temperatures in Brandon, South Dakota, vary between a high-temperature of 74.1°F (23.4°C) and a low-temperature of 53.2°F (11.8°C).