Freeport weather in August

In August, Freeport sees average daytime highs of 80°F and overnight lows near 62°F, with 3.7 in of rain across 9.9 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 80°F through the month. The sky is clear or mostly clear about 37% of the time in August, and the air most often feels comfortable.

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 Freeport's 2nd-clearest and 12th-windiest month. For the whole year in context, see Freeport's year-round climate.

Daytime high
80°
2nd warmest
Overnight low
62°
11th coldest
Rainfall
3.7 in
9.9 wet days
Daylight
13 h 42 min
5:11 AM – 6:54 PM
Cloud cover
54%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
5.45 kWh/m²
Travel score
6.7
out of 10

Freeport is city and county seat and largest city of Stephenson County, Illinois, United States.

Density
802/km²
people per km²
Founded
1827

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 Freeport reaches about 80°F in the afternoon and slips back to 62°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 73°F and 87°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)
18164
28164
38163
48163
58163
68163
78163
88163
98063
108062
118062
128062
138062
148062
158062
168062
178062
188062
198062
208062
218062
228062
238061
248061
257961
267961
277961
287960
297960
307960
317860

How August really feels in Freeport

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.

Freeport 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° / 15°1.87.55.89.30.0
Feb33° / 18°1.86.65.110.30.0
Mar46° / 29°2.69.52.911.61.2
Apr58° / 39°4.311.91.113.14.0
May69° / 50°4.413.1014.45.9
Jun79° / 60°4.3120156.3
Jul82° / 64°3.610.4014.86.4
Aug80° / 62°3.79.9013.76.7
Sep73° / 54°3.68.8012.37.0
Oct60° / 42°2.98.80.210.85.0
Nov46° / 31°2.47.81.79.61.3
Dec34° / 21°2.17.64.690.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% 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 44%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15743
25743
35743
45743
55743
65644
75644
85545
95545
105545
115545
125545
135545
145644
155644
165644
175644
185545
195545
205644
215545
225545
235644
245644
255644
265743
275743
285743
295743
305842
315842

Chance of precipitation in August

Any precipitation

Freeport gets around 3.7 in of rain over 9.9 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 32% and peaks near 33% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
131
231
331
431
531
631
731
831
931
1032
1132
1232
1333
1433
1533
1633
1733
1833
1933
2033
2133
2233
2333
2433
2532
2632
2731
2831
2930
3030
3129

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the comfortable band about 25% of days. Sticky, muggy-or-worse air turns up on roughly 33% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
113262425121
213262425111
313262425111
414262425110
514262524110
615252524110
715252524100
816252524100
916252524100
1017252524100
1117252523100
1218252523100
131824252390
141824252390
151824252390
161924252390
171924252390
181923252390
191923262490
201923252490
211923252490
221924252390
231924252390
241924252390
252024242290
262025242290
272125232190
282225232190
292326232080
302426222080
312626221970

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
226calm
236calm
246calm
256calm
266calm
276calm
286calm
297calm
307calm
317calm

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 4:55 AM to 5:27 AM, and sunset from 7:14 PM to 6:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.34:557:14
214.34:567:13
314.34:577:12
414.24:587:11
514.24:597:10
614.15:007:08
714.15:017:07
814.15:027:06
914.05:037:04
1014.05:047:03
1113.95:057:02
1213.95:067:00
1313.95:076:59
1413.85:096:57
1513.85:106:56
1613.75:116:54
1713.75:126:53
1813.65:136:51
1913.65:146:50
2013.65:156:48
2113.55:166:47
2213.55:176:45
2313.45:186:44
2413.45:196:42
2513.35:206:40
2613.35:226:39
2713.25:236:37
2813.25:246:35
2913.15:256:34
3013.15:266:32
3113.15:276:30

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.45 kWh/m².

For context, solar energy here swings from a low near 1.66 kWh/m² to a high of 6.32 kWh/m² in June across the year — August's 5.45 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.0Bright
25.9Bright
35.9Bright
45.9Bright
55.8Bright
65.8Bright
75.7Bright
85.7Bright
95.7Bright
105.6Bright
115.6Bright
125.6Bright
135.5Bright
145.5Bright
155.5Bright
165.4Bright
175.4Bright
185.4Bright
195.3Bright
205.3Bright
215.3Bright
225.3Bright
235.2Bright
245.2Bright
255.2Bright
265.2Bright
275.1Bright
285.1Bright
295.1Bright
305.1Bright
315.0Bright
Planning a trip in August

Is August a good time to visit Freeport?

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

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

What to pack for Freeport in August

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

In August, Freeport sees daytime highs around 80°F and nights near 62°F. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

UV index in Freeport 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 Freeport peaks around June 19 at about 9 (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 19UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Freeport 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 Freeport is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1915 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar13Moderate
Apr12Good
May13Moderate
Jun14Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Freeport?

Freeport sits at 42.3°N, 89.6°W, 778 ft above sea level, in United States. The nearest listed city is Rockford, 27 mi away.

Topography around Freeport

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

Within 2 miles, the terrain around Freeport has only modest variations in elevation — a maximum elevation change of 177 ft around an average of 797 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 472 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 853 ft.

The land around Freeport is covered by trees (33%), grassland (24%) and cropland (21%) within 2 miles, cropland (75%) within 10 miles, and cropland (67%) within 50 miles.

2 miles
177 ft
10 miles
472 ft
50 miles
853 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Rockford 27 mi · Loves Park 29 mi · Machesney Park 30 mi · Dixon 32 mi · Beloit 34 mi · Sterling 35 mi · Belvidere 40 mi · Janesville 40 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 Freeport (42.2967°, -89.6212°, elevation 778 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).