Sioux Falls Weather in September
In Sioux Falls, September brings high daytime temperatures around 24°C (75°F), with nights cooling to 10°C (50°F). Expect quite a bit of rainfall this month.
Rainfall in Sioux Falls in September
This month experiences about 9 days of rain according to historical data, averaging 71 mm (2.8 in). The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.
Temperature in Sioux Falls in September
If you're visiting Sioux Falls in September, expect perfect temperatures with highs of 24°C (75°F) and overnight lows of 10°C (50°F). Conditions stay fairly consistent through the month, making it easier to plan what to wear. Nights drop to around 10°C (50°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable.So this is a great month to visit if you prefer dry days with pleasant temperatures.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Sioux Falls's climate page.
Sioux Falls Temperature in September
Min Temperature
10°C (50°F)
Max Temperature
24°C (75°F)
Chance of Rain
30%
Precipitation
71 mm (2.8 in)
Rainy days
9 days
Humidity
69%
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Sioux Falls typically drop from around 27°C (81°F) at the start of September to approximately 22°C (72°F) by the end. Nights are cool, with lows typically ranging from 7°C (45°F) to 16°C (61°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Sioux Falls in September
Browse day-by-day weather records for Sioux Falls spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Sioux Falls historical weather extremes in September
Based on weather observations in Sioux Falls between 1976 and 2025, these are the recorded extremes during September.
- The hottest September day on record in Sioux Falls reached 40°C (104°F) (September 6, 1976).
- The lowest overnight temperature recorded in September was -4°C (25°F) (September 26, 1984).
Best Places in the United States of America in September
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in September →
perfect weather
pleasant
tolerable
unpleasant
poor
What to Wear in Sioux Falls in September
For Sioux Falls in September, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. Rain is likely on several days, so bring a good rain jacket.What To Do in Sioux Falls in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Sioux Falls's climate page.
See the full Sioux Falls climate overview or explore weather in the United States of America.
