Sioux Falls weather in August

In August, Sioux Falls sees average daytime highs of 80°F and overnight lows near 61°F, with 3.3 in of rain across 8.8 wet days and about 13.8 hours of daylight. It is the 2nd-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 80°F through the month. The sky is clear or mostly clear about 48% of the time in August, and the air most often feels humid.

Daylight stretches from about 14 h 24 min at the start of August to 13 h 06 min by month's end. Set against the rest of the year, August is Sioux Falls's 3rd-clearest and 11th-windiest month. For the whole year in context, see Sioux Falls's year-round climate.

Daytime high
80°
2nd warmest
Overnight low
61°
11th coldest
Rainfall
3.3 in
8.8 wet days
Daylight
13 h 48 min
5:37 AM – 7:25 PM
Cloud cover
45%
3rd clearest
Wind
8 mph
11th windiest
Solar energy
5.77 kWh/m²
Travel score
7.0
out of 10

Sioux Falls is city in and seat of Minnehaha County, and largest city in South Dakota, United States.

Density
872/km²
people per km²
Founded
1856

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 80°F through the month.

A typical August day in Sioux Falls reaches about 80°F in the afternoon and slips back to 61°F overnight — a 20°F spread between the day's warmth and the night's chill. On most days the high lands between 72°F and 88°F. Set against its neighbours, August runs about 2°F cooler than July and about 7°F warmer than September.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
18262
28262
38162
48162
58162
68162
78162
88162
98161
108061
118061
128061
138061
148061
158061
168061
178060
188060
198060
208060
218060
228060
238060
248060
258060
268060
278059
287959
297959
307959
317958

How August really feels in Sioux Falls

Once humidity and wind are folded in, August averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

August sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Sioux Falls weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan26° / 10°0.84.74.49.10.0
Feb31° / 13°0.94.84.410.20.0
Mar43° / 24°1.86.63.711.61.0
Apr57° / 36°3.610.32.213.24.0
May69° / 49°4.512.5014.55.9
Jun78° / 59°5.112.5015.26.4
Jul82° / 64°3.38.9014.96.5
Aug80° / 61°3.38.8013.87.0
Sep73° / 52°3.27.9012.37.2
Oct59° / 39°2.470.710.85.0
Nov43° / 25°1.65.53.19.50.9
Dec30° / 15°1.054.88.80.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 48% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 19% of August, with mostly cloudy or overcast conditions the remaining 33%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16832
26832
36832
46634
56634
66634
76535
86535
96535
106436
116436
126436
136436
146436
156436
166535
176535
186634
196634
206634
216733
226733
236733
246832
256832
266931
276931
287030
297030
307030
317030

Chance of precipitation in August

Any precipitation

Sioux Falls gets around 3.3 in of rain over 8.8 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 28% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
128
228
328
428
529
629
730
830
930
1031
1131
1231
1331
1431
1530
1630
1729
1829
1929
2028
2128
2227
2327
2426
2526
2625
2725
2825
2925
3025
3125

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

Most of August feels humid — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, August lands in the humid band about 27% of days. Sticky, muggy-or-worse air turns up on roughly 31% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
112242825101
21225282591
31225282691
41225282691
51225282691
61225272690
71226272690
81226282690
91226282680
101326282580
111326282580
121326282480
131426282480
141426282480
151526282480
161526282370
171626282370
181626282370
191626282370
201725282370
211725282460
221825282460
231924272460
242024272460
252123272460
262223272450
272322262350
282522262340
292622252340
302821252230
313021242130

Wind in August

Winds average 8 mph in August.

Across August, daily wind ranges from about 8 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light breeze
319light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 24 min at the start of August to 13 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over August. Sunrise moves from 5:20 AM to 5:54 AM, and sunset from 7:46 PM to 7:00 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.45:207:46
214.45:217:45
314.45:227:44
414.35:237:42
514.35:247:41
614.25:257:40
714.25:277:38
814.25:287:37
914.15:297:36
1014.15:307:34
1114.05:317:33
1214.05:327:31
1313.95:337:30
1413.95:347:28
1513.95:367:27
1613.85:377:25
1713.85:387:24
1813.75:397:22
1913.75:407:20
2013.65:417:19
2113.65:427:17
2213.55:447:16
2313.55:457:14
2413.45:467:12
2513.45:477:10
2613.35:487:09
2713.35:497:07
2813.25:517:05
2913.25:527:03
3013.15:537:02
3113.15:547:00

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.77 kWh/m².

For context, solar energy here swings from a low near 1.73 kWh/m² to a high of 6.67 kWh/m² in July across the year — August's 5.77 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.3Intense
26.2Intense
36.2Intense
46.1Intense
56.1Intense
66.0Intense
76.0Intense
86.0Bright
95.9Bright
105.9Bright
115.9Bright
125.9Bright
135.8Bright
145.8Bright
155.8Bright
165.8Bright
175.7Bright
185.7Bright
195.7Bright
205.7Bright
215.7Bright
225.6Bright
235.6Bright
245.6Bright
255.5Bright
265.5Bright
275.5Bright
285.5Bright
295.4Bright
305.4Bright
315.3Bright
Planning a trip in August

Hazard calendar for Sioux Falls

In seasonPeak

In August, Sioux Falls sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Sioux Falls's rainy season runs April–October, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is August a good time to visit Sioux Falls?

Our two travel scores rate August for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.0
Sightseeing
2nd-best month of the year
7.0
Beach & pool
2nd-best month of the year

August is one of the better times to visit Sioux Falls for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Sioux Falls in August

From August's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In August, Sioux Falls sees daytime highs around 80°F and nights near 61°F. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Sioux Falls in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sioux Falls peaks around June 16 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 16UV 8Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr5High
May6High
Jun9Very high
Jul6High
Aug7High
Sep6High
Oct4Moderate
Nov2Moderate
Dec2Low
Location & terrain

Where is Sioux Falls?

Sioux Falls sits at 43.5°N, 96.7°W, 1,470 ft above sea level, in United States. The nearest listed city is Brookings, 53 mi away.

Topography around Sioux Falls

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Sioux Falls.

Within 2 miles, the terrain around Sioux Falls has only modest variations in elevation — a maximum elevation change of 246 ft around an average of 1,440 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 390 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 843 ft.

The land around Sioux Falls is covered by artificial surfaces (47%) and trees (37%) within 2 miles, cropland (51%) and grassland (25%) within 10 miles, and cropland (83%) within 50 miles.

2 miles
246 ft
10 miles
390 ft
50 miles
843 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Brookings 53 mi · Mitchell 66 mi · Sioux City 74 mi · Watertown 96 mi · Norfolk 111 mi · Willmar 137 mi · Mankato 142 mi · Fremont 146 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sioux Falls (43.5437°, -96.728°, elevation 1,470 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).