Sioux City weather in August

In August, Sioux City sees average daytime highs of 82°F and overnight lows near 63°F, with 3.9 in of rain across 9.4 wet days and about 13.7 hours of daylight. It is the 2nd-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 82°F through the month. The sky is clear or mostly clear about 47% of the time in August, and the air most often feels humid.

Daylight stretches from about 14 h 18 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 City's 3rd-clearest and 11th-windiest month. For the whole year in context, see Sioux City's year-round climate.

Daytime high
82°
2nd warmest
Overnight low
63°
11th coldest
Rainfall
3.9 in
9.4 wet days
Daylight
13 h 42 min
5:37 AM – 7:22 PM
Cloud cover
46%
3rd clearest
Wind
8 mph
11th windiest
Solar energy
5.77 kWh/m²
Travel score
6.6
out of 10

Sioux City is city in Woodbury and Plymouth counties in Iowa, United States.

Density
547/km²
people per km²
Founded
1854

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 82°F through the month.

A typical August day in Sioux City reaches about 82°F in the afternoon and slips back to 63°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 74°F and 91°F. Set against its neighbours, August runs about 2°F cooler than July and about 7°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18365
28364
38364
48364
58364
68364
78364
88264
98264
108264
118263
128263
138263
148263
158263
168263
178263
188263
198262
208262
218262
228262
238262
248262
258262
268262
278162
288161
298161
308161
318160

How August really feels in Sioux City

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 City 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
Jan29° / 13°0.94.74.39.20.0
Feb34° / 16°1.154.410.30.0
Mar47° / 27°2.273.211.61.6
Apr60° / 39°4.010.61.813.14.6
May71° / 51°4.912.60.114.46.2
Jun80° / 61°4.911.8015.16.3
Jul84° / 65°3.08.8014.85.8
Aug82° / 63°3.99.4013.76.6
Sep75° / 54°3.07.7012.37.4
Oct62° / 41°2.47.40.510.85.6
Nov46° / 28°1.65.42.59.61.5
Dec33° / 17°1.25.24.28.90.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 47% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 18% of August, with mostly cloudy or overcast conditions the remaining 35%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16733
26535
36535
46535
56436
66337
76337
86238
96238
106139
116139
126139
136139
146139
156238
166238
176337
186436
196436
206436
216535
226535
236634
246733
256832
266832
276931
287030
297129
307129
317129

Chance of precipitation in August

Any precipitation

Sioux City gets around 3.9 in of rain over 9.4 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 30% and peaks near 33% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
129
230
330
431
531
632
732
832
933
1033
1133
1233
1333
1432
1532
1631
1730
1830
1929
2029
2129
2228
2328
2427
2527
2626
2726
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 30% of days. Sticky, muggy-or-worse air turns up on roughly 39% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
16212827162
26212827162
36212827152
46212928152
56212928152
66212928151
76212928141
87212928141
97212928141
107213028131
118213028131
128213028131
138203128121
149203128121
159203127121
1610203127121
1710203127110
1810203127110
1910203127110
2011203128110
2111203028110
2211203028100
2312213027100
2412213027100
251321302790
261421292790
271521292690
281721292680
291821282570
302021282470
312221272360

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
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
279light breeze
289light breeze
299light breeze
309light breeze
319light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 18 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 72 minutes over August. Sunrise moves from 5:21 AM to 5:54 AM, and sunset from 7:42 PM to 6:57 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.35:217:42
214.35:227:41
314.35:237:40
414.25:257:38
514.25:267:37
614.25:277:36
714.15:287:35
814.15:297:33
914.05:307:32
1014.05:317:31
1114.05:327:29
1213.95:337:28
1313.95:347:26
1413.85:357:25
1513.85:367:23
1613.75:377:22
1713.75:397:20
1813.75:407:19
1913.65:417:17
2013.65:427:16
2113.55:437:14
2213.55:447:13
2313.45:457:11
2413.45:467:09
2513.35:477:08
2613.35:487:06
2713.25:497:04
2813.25:517:03
2913.25:527:01
3013.15:536:59
3113.15:546:57

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 1.82 kWh/m² to a high of 6.66 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
125.8Bright
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
315.4Bright
Planning a trip in August

Hazard calendar for Sioux City

In seasonPeak

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

Sioux City'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 City?

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

6.6
Sightseeing
2nd-best month of the year
7.1
Beach & pool
2nd-best month of the year

August is a reasonable time to visit Sioux City for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Sioux City in August

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

In August, Sioux City sees daytime highs around 82°F and nights near 63°F. Pack light clothes. Worth having: rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

UV index in Sioux City 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 City peaks around June 19 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 19UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May6High
Jun9Very high
Jul8Very high
Aug7High
Sep6High
Oct4Moderate
Nov2Moderate
Dec2Low
Location & terrain

Where is Sioux City?

Sioux City sits at 42.5°N, 96.4°W, 1,201 ft above sea level, in United States. The nearest listed city is Norfolk, 62 mi away.

Topography around Sioux City

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

Within 2 miles, the terrain around Sioux City has only modest variations in elevation — a maximum elevation change of 282 ft around an average of 1,152 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 436 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 892 ft.

The land around Sioux City is covered by artificial surfaces (46%) and trees (30%) within 2 miles, cropland (52%) and grassland (23%) within 10 miles, and cropland (84%) within 50 miles.

2 miles
282 ft
10 miles
436 ft
50 miles
892 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Norfolk 62 mi · Fremont 74 mi · Sioux Falls 74 mi · Columbus 89 mi · Omaha 89 mi · Council Bluffs 90 mi · La Vista 93 mi · Papillion 95 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 City (42.5°, -96.4003°, elevation 1,201 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).