Sterling weather in August

In August, Sterling sees average daytime highs of 81°F and overnight lows near 63°F, with 3.3 in of rain across 9.1 wet days and about 13.7 hours of daylight. It is the 2nd-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 81°F through the month. The sky is clear or mostly clear about 39% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 h 18 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Sterling's 2nd-clearest and 12th-windiest month. For the whole year in context, see Sterling's year-round climate.

Daytime high
81°
2nd warmest
Overnight low
63°
11th coldest
Rainfall
3.3 in
9.1 wet days
Daylight
13 h 42 min
5:12 AM – 6:54 PM
Cloud cover
52%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
5.53 kWh/m²
Travel score
6.7
out of 10

Sterling is city in Whiteside County, Illinois, United States.

Density
978/km²
people per km²
Founded
1838

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 81°F through the month.

A typical August day in Sterling reaches about 81°F in the afternoon and slips back to 63°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 74°F and 88°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)
18265
28265
38264
48264
58264
68264
78264
88264
98164
108164
118164
128163
138163
148163
158163
168163
178163
188163
198163
208163
218163
228163
238163
248162
258162
268162
278162
288062
298062
308061
318061

How August really feels in Sterling

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.

Sterling weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan30° / 15°1.97.65.19.30.0
Feb35° / 19°1.96.74.210.30.0
Mar48° / 30°2.69.42.411.71.7
Apr60° / 41°4.311.50.813.14.6
May71° / 52°4.713.2014.36.0
Jun80° / 62°4.5120156.3
Jul83° / 65°3.710.1014.76.0
Aug81° / 63°3.39.1013.76.7
Sep75° / 55°3.48.3012.37.1
Oct62° / 43°2.98.50.210.95.5
Nov47° / 32°2.57.71.39.61.7
Dec35° / 22°2.27.5490.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 39% 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 43%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15941
25941
35941
45941
55941
65842
75743
85743
95743
105644
115644
125644
135644
145644
155743
165743
175743
185644
195644
205644
215644
225545
235644
245644
255743
265842
275842
285941
296040
306040
316040

Chance of precipitation in August

Any precipitation

Sterling gets around 3.3 in of rain over 9.1 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 29% and peaks near 30% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
130
230
330
430
530
629
729
829
929
1029
1130
1230
1330
1430
1530
1630
1730
1830
1930
2030
2130
2230
2330
2430
2529
2629
2729
2828
2928
3028
3128

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the muggy band about 26% 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 (%)
18222627161
29232526161
39232526161
49242526161
59242526151
69242526151
710242525151
810242525141
911242625141
1011242625141
1111242625131
1212242625131
1312232625131
1412232625131
1513232625120
1613222726120
1713222626120
1813222626120
1914212627120
2014212627120
2114212627120
2214222527120
2314222527120
2414232427120
2515232427120
2615242326120
2716242226110
2817252225110
2918262124110
3019262124100
3120272023100

Wind in August

Winds average 6 mph in August, the calmest month.

Across August, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 18 min at the start of August to 13 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 78 minutes over August. Sunrise moves from 4:56 AM to 5:28 AM, and sunset from 7:13 PM to 6:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.34:567:13
214.24:577:12
314.24:587:11
414.24:597:10
514.15:007:09
614.15:017:07
714.15:027:06
814.05:047:05
914.05:057:04
1013.95:067:02
1113.95:077:01
1213.95:087:00
1313.85:096:58
1413.85:106:57
1513.75:116:55
1613.75:126:54
1713.75:136:52
1813.65:146:51
1913.65:156:49
2013.55:166:48
2113.55:176:46
2213.45:186:45
2313.45:196:43
2413.45:206:41
2513.35:216:40
2613.35:236:38
2713.25:246:37
2813.25:256:35
2913.15:266:33
3013.15:276:31
3113.05:286:30

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.53 kWh/m².

For context, solar energy here swings from a low near 1.71 kWh/m² to a high of 6.34 kWh/m² in June across the year — August's 5.53 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.0Intense
26.0Intense
36.0Bright
45.9Bright
55.9Bright
65.9Bright
75.8Bright
85.8Bright
95.8Bright
105.7Bright
115.7Bright
125.7Bright
135.6Bright
145.6Bright
155.5Bright
165.5Bright
175.5Bright
185.5Bright
195.4Bright
205.4Bright
215.4Bright
225.3Bright
235.3Bright
245.3Bright
255.3Bright
265.2Bright
275.2Bright
285.2Bright
295.2Bright
305.1Bright
315.1Bright
Planning a trip in August

Is August a good time to visit Sterling?

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

6.7
Sightseeing
2nd-best month of the year
6.9
Beach & pool
2nd-best month of the year

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

What to pack for Sterling in August

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

In August, Sterling sees daytime highs around 81°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 Sterling in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sterling peaks around June 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 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 9Dec 19UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Sterling 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 Sterling is worst in July — around 15 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodJul 1915 µg/m³Oct 227 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar13Moderate
Apr11Good
May13Moderate
Jun13Moderate
Jul15Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov8Good
Dec9Good
Location & terrain

Where is Sterling?

Sterling sits at 41.8°N, 89.7°W, 659 ft above sea level, in United States. The nearest listed city is Dixon, 12 mi away.

Topography around Sterling

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

Within 2 miles, the terrain around Sterling has only modest variations in elevation — a maximum elevation change of 121 ft around an average of 656 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 295 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 830 ft.

The land around Sterling is covered by trees (28%) and artificial surfaces (28%) within 2 miles, cropland (81%) within 10 miles, and cropland (77%) within 50 miles.

2 miles
121 ft
10 miles
295 ft
50 miles
830 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Dixon 12 mi · Clinton 25 mi · Freeport 35 mi · East Moline 43 mi · Rockford 45 mi · Bettendorf 46 mi · Moline 47 mi · Davenport 49 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 Sterling (41.7886°, -89.6962°, elevation 659 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).