Waterloo weather in August

In August, Waterloo sees average daytime highs of 80°F and overnight lows near 61°F, with 3.9 in of rain across 9.5 wet days and about 13.7 hours of daylight. It is the 2nd-warmest and 5th-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 42% 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 Waterloo's 2nd-clearest and 12th-windiest month. For the whole year in context, see Waterloo's year-round climate.

Daytime high
80°
2nd warmest
Overnight low
61°
11th coldest
Rainfall
3.9 in
9.5 wet days
Daylight
13 h 42 min
5:21 AM – 7:06 PM
Cloud cover
51%
2nd clearest
Wind
7 mph
12th windiest
Solar energy
5.57 kWh/m²
Travel score
6.8
out of 10

Waterloo is city in Black Hawk County, Iowa, United States.

Density
418/km²
people per km²
Founded
1868

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 Waterloo reaches about 80°F in the afternoon and slips back to 61°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 72°F and 87°F. Set against its neighbours, August runs about 2°F cooler than July and about 6°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18163
28163
38163
48063
58063
68062
78062
88062
98062
108062
118062
128062
138062
148062
158061
167961
177961
187961
197961
207961
217961
227961
237961
247961
257960
267960
277960
287960
297960
307959
317859

How August really feels in Waterloo

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.

Waterloo weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan26° / 11°1.46.85.69.20.0
Feb31° / 15°1.46.54.810.30.0
Mar45° / 27°2.593.411.61.1
Apr59° / 39°4.311.21.113.14.3
May70° / 51°5.0130.114.46.0
Jun79° / 61°5.112.4015.16.3
Jul82° / 64°4.210.3014.86.5
Aug80° / 61°3.99.5013.76.8
Sep73° / 53°3.78.6012.37.1
Oct60° / 41°2.88.30.410.85.2
Nov45° / 29°2.17.22.19.61.2
Dec32° / 18°1.76.95.18.90.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 42% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 17% of August, with mostly cloudy or overcast conditions the remaining 41%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15842
25842
35842
45842
55941
65842
75842
85842
95743
105743
115743
125743
135743
145842
155842
165842
175842
185842
195941
205941
215941
225842
235842
245941
255941
266040
276139
286139
296139
306238
316337

Chance of precipitation in August

Any precipitation

Waterloo gets around 3.9 in of rain over 9.5 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 32% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
129
229
329
429
530
630
730
830
931
1031
1131
1232
1332
1432
1532
1632
1732
1832
1932
2032
2132
2231
2331
2431
2530
2629
2728
2828
2927
3027
3126

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 26% of days. Sticky, muggy-or-worse air turns up on roughly 37% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
18233024151
28233024141
38233024141
49232924141
59232925131
69232925131
710232925131
810232825121
911232826120
1011232826120
1112232726110
1212232726110
1312232726110
1412242727100
1512242727100
1613242627100
1713242628100
181324262890
191324262890
201324262890
211424262890
221424252890
231424252890
241524252790
251625242780
261725242680
271825232680
281925232580
292125232480
302325222370
312525222270

Wind in August

Winds average 7 mph in August, the calmest month.

Across August, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247light breeze
257light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light 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 5:05 AM to 5:38 AM, and sunset from 7:26 PM to 6:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.35:057:26
214.35:067:25
314.35:077:23
414.25:087:22
514.25:097:21
614.25:107:20
714.15:117:18
814.15:137:17
914.05:147:16
1014.05:157:14
1114.05:167:13
1213.95:177:12
1313.95:187:10
1413.85:197:09
1513.85:207:07
1613.75:217:06
1713.75:227:04
1813.75:237:03
1913.65:247:01
2013.65:267:00
2113.55:276:58
2213.55:286:56
2313.45:296:55
2413.45:306:53
2513.35:316:51
2613.35:326:50
2713.25:336:48
2813.25:346:46
2913.25:356:45
3013.15:376:43
3113.15:386:41

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.57 kWh/m².

For context, solar energy here swings from a low near 1.7 kWh/m² to a high of 6.37 kWh/m² in July across the year — August's 5.57 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.1Intense
26.0Intense
36.0Intense
46.0Bright
55.9Bright
65.9Bright
75.9Bright
85.8Bright
95.8Bright
105.8Bright
115.7Bright
125.7Bright
135.7Bright
145.6Bright
155.6Bright
165.5Bright
175.5Bright
185.5Bright
195.5Bright
205.4Bright
215.4Bright
225.4Bright
235.4Bright
245.3Bright
255.3Bright
265.3Bright
275.3Bright
285.2Bright
295.2Bright
305.2Bright
315.2Bright
Planning a trip in August

Is August a good time to visit Waterloo?

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

6.8
Sightseeing
2nd-best month of the year
6.7
Beach & pool
2nd-best month of the year

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

What to pack for Waterloo in August

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

In August, Waterloo sees daytime highs around 80°F and nights near 61°F. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

UV index in Waterloo 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 Waterloo peaks around June 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 18UV 9Jan 1UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May7Very high
Jun9Very high
Jul8Very high
Aug7Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Waterloo in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Waterloo is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateGoodJul 1916 µg/m³Oct 217 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar14Moderate
Apr11Good
May12Good
Jun13Moderate
Jul16Moderate
Aug15Moderate
Sep12Good
Oct7Good
Nov8Good
Dec10Good
Location & terrain

Where is Waterloo?

Waterloo sits at 42.5°N, 92.3°W, 856 ft above sea level, in United States. The nearest listed city is Cedar Falls, 5.6 mi away.

Topography around Waterloo

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

Within 2 miles, the terrain around Waterloo has only modest variations in elevation — a maximum elevation change of 151 ft around an average of 873 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 243 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 620 ft.

The land around Waterloo is covered by trees (39%) and artificial surfaces (39%) within 2 miles, cropland (64%) within 10 miles, and cropland (81%) within 50 miles.

2 miles
151 ft
10 miles
243 ft
50 miles
620 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Cedar Falls 5.6 mi · Marshalltown 42 mi · Cedar Rapids 49 mi · Marion 50 mi · Mason City 63 mi · North Liberty 64 mi · Newton 66 mi · Coralville 68 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 Waterloo (42.4928°, -92.343°, elevation 856 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).