Sioux Falls, SD weather in September
September in Sioux Falls: mild, with some rain. Highs 76°F, lows 52°F, about 8 days with rain. A good month for most outdoor plans.
- Normal high
- 76°F
- Normal low
- 52°F
- Wet days
- 8
- 2.7 in total
- Muggy days
- 2
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 80°F | 70°F |
| Normal low | 58°F | 46°F |
| Chance of a wet day | 28% | 27% |
| Sunrise / sunset | 6:50 am / 8:02 pm | 7:23 am / 7:10 pm |
| Daylight | 13.2 h | 11.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Central Time).
A typical September day
- 6 am54°Fdew point 50°F
- 9 am62°Fdew point 53°F
- Noon70°Fdew point 53°F
- 3 pm73°Fdew point 52°F
- 6 pm69°Fdew point 52°F
- 9 pm61°Fdew point 52°F
NOAA hourly normals (local standard time) from Sioux Falls (3 mi away); average wind 10 mph; clear or few clouds in 60% of daytime hours, mostly cloudy or overcast in 29%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F14 of 30
- Hot dayshigh 90°F or more1 of 30
- Muggy daysdaily mean dew point 65°F or more2 of 30
- Wet daysat least 0.01 in of rain or melted snow8 of 30
- Notable rainat least 0.10 in5 of 30
- Freezing nightslow 32°F or below1 of 30
- Snow on the groundsnow depth 1 in or more0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 2.7 in; a dry September brings about 1.4 in and a wet one about 3.9 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How September varies from year to year
- Warmest September, 1991-20201998: average high 80°F
- Coolest September1993: average high 68°F
- Wettest September2016: 7.5 in
- Driest September2011: 0.2 in
- Highest reading96°F (September 11, 2012)
- Lowest reading27°F (September 23, 2012)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 83°F | 76°F | 61°F |
| Normal low | 61°F | 52°F | 38°F |
| Wet days | 9 | 8 | 8 |
| Comfortable days | 8 | 14 | 10 |
| Daylight | 13.9 h | 12.5 h | 11.0 h |
Highs change by -7°F from August and -15°F into October.
How Sioux Falls ranks in September
- Normal high269th warmest of 378 cities; 2nd of 4 in South Dakota
- Wet days201st driest of 378
- Comfortable days100th most of 342
What to pack for Sioux Falls in September
- A rain jacket or umbrella – rain on about 8 days
Heating and cooling
September has 126 heating degree days and 89 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Sioux Falls in September?
The normal high is 76°F and the normal low is 52°F. From 1991 to 2020 the hottest September reading was 96°F (most recently on September 11, 2012).
Does it rain a lot in Sioux Falls in September?
About 8 days in September have at least 0.01 in of precipitation, and the normal total is 2.7 in. The wettest September in 1991-2020 was in 2016 (7.6 in); the driest was in 2011 (0.2 in).
Is September a good time to visit Sioux Falls?
September ranks 2nd of 12 months on our comfort score for Sioux Falls (68 out of 100). It has about 14 comfortable days and about 1 day at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Sioux Falls (USW00014944), 3.0 mi NNW of the city center, 1,430 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Joe Foss Field Airport (726510-14944), 3.3 mi NW of the city center, 1,419 ft (54 ft lower than the city). Hourly observations, 1991-2020.