Sioux Falls weather in September: Sioux Falls, South Dakota: normal highs, lows, rain and records for September
Sioux Falls in September has a normal high of 76°F and a normal low of 52°F, a daily mean of 64°F, falling from 80°F on the 1st to 70°F by the 30th. Measurable precipitation falls on 8 days in a normal September, 2.73 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 24°C and low of 11°C, 69 mm of precipitation in September.
- NOAA stationSioux Falls Foss Field
- Station IDUSW00014944
- Location43.59°N 96.73°W
- Elevation1,430 ft (436 m)
- From the center3 miles
- Population209,289
- Jan 27° 9°
- Feb 32° 13°
- Mar 45° 24°
- Apr 59° 36°
- May 71° 48°
- Jun 81° 59°
- Jul 85° 63°
- Aug 83° 61°
- Sep 76° 52°
- Oct 61° 38°
- Nov 45° 25°
- Dec 32° 13°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Sioux Falls in September?
The normal high is 76°F and the normal low 52°F, for a daily mean of 63.8°F. September is 8.2°F cooler than August and 14.2°F warmer than October. September is the 4th warmest month of the year in Sioux Falls and the 6th wettest. Across the month the normal high falls 10°F, from 80°F on September 1 to 70°F on September 30. From one year to the next September's mean temperature typically moves about 3.0°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 61°F and 67°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 28%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 80°F | 58°F | 28% | 16% |
| September 8 | 78°F | 55°F | 28% | 16% |
| September 15 | 76°F | 52°F | 28% | 16% |
| September 22 | 74°F | 49°F | 27% | 16% |
| September 30 | 70°F | 46°F | 27% | 15% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 80°F | 58°F | 28% | 16% | 13 h 20 min |
| September 2 | 80°F | 57°F | 28% | 16% | 13 h 10 min |
| September 3 | 80°F | 57°F | 28% | 16% | 13 h 10 min |
| September 4 | 79°F | 57°F | 28% | 16% | 13 h 10 min |
| September 5 | 79°F | 56°F | 28% | 16% | 13 h |
| September 6 | 79°F | 56°F | 28% | 16% | 13 h |
| September 7 | 79°F | 56°F | 28% | 16% | 13 h |
| September 8 | 78°F | 55°F | 28% | 16% | 13 h |
| September 9 | 78°F | 55°F | 28% | 16% | 12 h 50 min |
| September 10 | 78°F | 54°F | 28% | 16% | 12 h 50 min |
| September 11 | 78°F | 54°F | 28% | 16% | 12 h 50 min |
| September 12 | 77°F | 54°F | 28% | 16% | 12 h 40 min |
| September 13 | 77°F | 53°F | 28% | 16% | 12 h 40 min |
| September 14 | 77°F | 53°F | 28% | 16% | 12 h 40 min |
| September 15 | 76°F | 52°F | 28% | 16% | 12 h 30 min |
| September 16 | 76°F | 52°F | 27% | 16% | 12 h 30 min |
| September 17 | 76°F | 52°F | 27% | 16% | 12 h 30 min |
| September 18 | 75°F | 51°F | 27% | 16% | 12 h 30 min |
| September 19 | 75°F | 51°F | 27% | 16% | 12 h 20 min |
| September 20 | 74°F | 50°F | 27% | 16% | 12 h 20 min |
| September 21 | 74°F | 50°F | 27% | 16% | 12 h 20 min |
| September 22 | 74°F | 49°F | 27% | 16% | 12 h 10 min |
| September 23 | 73°F | 49°F | 27% | 16% | 12 h 10 min |
| September 24 | 73°F | 48°F | 27% | 16% | 12 h 10 min |
| September 25 | 72°F | 48°F | 27% | 16% | 12 h 10 min |
| September 26 | 72°F | 47°F | 27% | 16% | 12 h |
| September 27 | 71°F | 47°F | 27% | 15% | 12 h |
| September 28 | 71°F | 47°F | 27% | 15% | 12 h |
| September 29 | 70°F | 46°F | 27% | 15% | 11 h 50 min |
| September 30 | 70°F | 46°F | 27% | 15% | 11 h 50 min |
- Normal high
- 76°FSeptember average
- Normal low
- 52°FSeptember average
- Precipitation
- 2.73 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 1
- Nights at 32°F or colder
- 1
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 21
- Days at 80°F or more
- 10
- Sunshine
- 79%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014944; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Sioux Falls in September?
On a given September day the chance of 0.01 inch or more is 27% on average, highest around September 1 (28%). In all, 2.73 in falls on 8 days of a normal September, 1 of them with an inch or more.
In a normal September in Sioux Falls, 1 days reach 90°F and 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014944.
How humid and windy is Sioux Falls in September?
At 3 p.m. the normal temperature is 67°F with 45% relative humidity and a dew point of 45°F; at 6 a.m. it is 48°F with 83% humidity. The wind averages 9.5 mph, most often from the west-southwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 48°F | 43°F | 83% | 7.3 mph | 58% |
| 9 a.m. | 55°F | 45°F | 70% | 10.7 mph | 65% |
| noon | 64°F | 45°F | 51% | 12.9 mph | 53% |
| 3 p.m. | 67°F | 45°F | 45% | 13.3 mph | 65% |
| 6 p.m. | 62°F | 45°F | 53% | 9.2 mph | 56% |
| 9 p.m. | 55°F | 45°F | 69% | 8.2 mph | 69% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014944. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Sioux Falls?
The warmest September temperature on Sioux Falls's official record (since 1893) is 104°F, on September 6, 1913; the coldest is 13°F, on September 29, 1899. The wettest September brought 9.26 in (1986).
The September mean against the 1991-2020 normal of 63.8°F: 2021 67.0°F (+3.2), 2022 66.7°F (+2.9), 2023 69.5°F (+5.7), 2024 68.7°F (+4.9), 2025 66.9°F (+3.1), 2026 67.5°F (+3.7). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 67.0°F | +3.2°F | 3.21 in |
| 2022 | 66.7°F | +2.9°F | 1.94 in |
| 2023 | 69.5°F | +5.7°F | 0.51 in |
| 2024 | 68.7°F | +4.9°F | 0.04 in |
| 2025 | 66.9°F | +3.1°F | 0.22 in |
| 2026 | 67.5°F | +3.7°F | 5.79 in |
Source: records: ACIS, NWS threaded record FSDthr; recent months: ACIS, station USW00014944. Records and recent months use complete months only.
How does September in Sioux Falls compare across South Dakota?
Across the 100 places PlainClimate covers in South Dakota, September normal highs run from 69°F in Custer to 82°F in Interior; Sioux Falls's is 76°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Sioux Falls in August83°F by day, 61°F at night
- Sioux Falls in October61°F by day, 38°F at night
- Sioux Falls through the yearEvery month, frost dates, records and recent years
- South Dakota in SeptemberThe statewide normal and the warmest and coolest places
- Interior: South Dakota's warmest Septembernormal high 82°F