Sioux Falls, SD weather in August
Expect warm, often humid weather with some rain in Sioux Falls in August, with highs near 83°F and lows near 61°F. Rain falls on about 9 days. It is one of the warmest months in Sioux Falls. Good for outdoor plans.
- Normal high
- 83°F
- Normal low
- 61°F
- Wet days
- 9
- 3.3 in total
- Muggy days
- 10
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 85°F | 80°F |
| Normal low | 63°F | 58°F |
| Chance of a wet day | 31% | 29% |
| Sunrise / sunset | 6:16 am / 8:49 pm | 6:49 am / 8:04 pm |
| Daylight | 14.6 h | 13.3 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 August day
- 6 am63°Fdew point 59°F
- 9 am71°Fdew point 62°F
- Noon77°Fdew point 62°F
- 3 pm80°Fdew point 62°F
- 6 pm78°Fdew point 63°F
- 9 pm70°Fdew point 63°F
NOAA hourly normals (local standard time) from Sioux Falls (3 mi away); average wind 9 mph; clear or few clouds in 59% of daytime hours, mostly cloudy or overcast in 25%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F8 of 31
- Hot dayshigh 90°F or more4 of 31
- Muggy daysdaily mean dew point 65°F or more10 of 31
- Wet daysat least 0.01 in of rain or melted snow9 of 31
- Notable rainat least 0.10 in5 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 3.3 in; a dry August brings about 1.8 in and a wet one about 5.1 in (25th and 75th percentiles). About 3 days bring half an inch or more, and about 1 an inch or more.
How August varies from year to year
- Warmest August, 1991-20201995: average high 88°F
- Coolest August1992: average high 76°F
- Wettest August2002: 8.3 in
- Driest August1999: 0.8 in
- Highest reading104°F (August 30, 2012)
- Lowest reading39°F (August 19, 2004)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 85°F | 83°F | 76°F |
| Normal low | 63°F | 61°F | 52°F |
| Wet days | 9 | 9 | 8 |
| Comfortable days | 5 | 8 | 14 |
| Daylight | 15.1 h | 13.9 h | 12.5 h |
Highs change by -2°F from July and -7°F into September.
How Sioux Falls ranks in August
- Normal high258th warmest of 378 cities; 3rd of 4 in South Dakota
- Wet days215th driest of 378
- Comfortable days88th most of 341
What to pack for Sioux Falls in August
- A rain jacket or umbrella – rain on about 9 days
Heating and cooling
August has 12 heating degree days and 227 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Sioux Falls in August?
The normal high is 83°F and the normal low is 61°F. From 1991 to 2020 the hottest August reading was 104°F (August 30, 2012).
Does it rain a lot in Sioux Falls in August?
About 9 days in August have at least 0.01 in of precipitation, and the normal total is 3.3 in. The wettest August in 1991-2020 was in 2002 (8.3 in); the driest was in 1999 (0.8 in).
Is August a good time to visit Sioux Falls?
August ranks 4th of 12 months on our comfort score for Sioux Falls (62 out of 100). It has about 8 comfortable days and about 4 days 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.