Algonquin weather in August

In August, Algonquin sees average daytime highs of 80°F and overnight lows near 63°F, with 3.6 in of rain across 10.6 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 35% 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 hours by month's end. Set against the rest of the year, August is Algonquin's 2nd-clearest and 12th-windiest month. For the whole year in context, see Algonquin's year-round climate.

Daytime high
80°
2nd warmest
Overnight low
63°
11th coldest
Rainfall
3.6 in
10.6 wet days
Daylight
13 h 42 min
5:06 AM – 6:49 PM
Cloud cover
55%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
5.37 kWh/m²
Travel score
6.6
out of 10

Algonquin is village in Illinois.

Founded
1890

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 Algonquin reaches about 80°F in the afternoon and slips back to 63°F overnight — a 16°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 7°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18165
28165
38165
48165
58164
68164
78064
88064
98064
108064
118064
128064
138064
148064
158064
168063
178063
188063
197963
207963
217963
227963
237963
247963
257963
267962
277962
287962
297962
307862
317861

How August really feels in Algonquin

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.

Algonquin 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
Jan30° / 17°2.07.969.30.0
Feb34° / 20°1.975.210.30.0
Mar45° / 29°2.59.73.311.61.1
Apr57° / 39°4.312.31.113.13.7
May68° / 50°4.312.2014.45.9
Jun78° / 61°3.811.80156.4
Jul82° / 65°3.410.4014.86.4
Aug80° / 63°3.610.6013.76.6
Sep73° / 55°3.08.8012.37.0
Oct60° / 44°3.08.70.210.85.0
Nov46° / 33°2.47.81.69.61.4
Dec35° / 22°2.184.690.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% 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 46%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15545
25545
35446
45446
55446
65347
75347
85347
95347
105347
115347
125248
135248
145347
155347
165347
175347
185347
195347
205347
215347
225446
235347
245347
255446
265545
275545
285743
295743
305743
315842

Chance of precipitation in August

Any precipitation

Algonquin gets around 3.6 in of rain over 10.6 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 34% and peaks near 35% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
134
234
334
434
534
634
734
834
934
1034
1134
1234
1335
1435
1535
1635
1735
1835
1935
2035
2135
2234
2334
2434
2533
2632
2731
2830
2930
3029
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 26% of days. Sticky, muggy-or-worse air turns up on roughly 34% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
111272525121
211272525121
311272525111
411272525111
511272624111
611272624110
712262624110
812262624110
913262723110
1013262723110
1114252723110
1214252723110
1314252723100
1414252724100
1515252724100
1615252724100
171525272590
181525262590
191525262690
201425262690
211425262690
221425262780
231426252780
241426252780
251527242680
261527242680
271628242580
281728232470
291828232470
301929222370
312129222270

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
296calm
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 4:50 AM to 5:22 AM, and sunset from 7:09 PM to 6:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.34:507:09
214.34:517:08
314.24:527:06
414.24:537:05
514.24:547:04
614.14:557:03
714.14:567:01
814.14:577:00
914.04:586:59
1014.04:596:57
1113.95:006:56
1213.95:016:55
1313.85:026:53
1413.85:036:52
1513.85:056:50
1613.75:066:49
1713.75:076:47
1813.65:086:46
1913.65:096:44
2013.55:106:43
2113.55:116:41
2213.55:126:40
2313.45:136:38
2413.45:146:36
2513.35:156:35
2613.35:166:33
2713.25:186:31
2813.25:196:30
2913.15:206:28
3013.15:216:26
3113.05:226:25

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.37 kWh/m².

For context, solar energy here swings from a low near 1.6 kWh/m² to a high of 6.32 kWh/m² in June across the year — August's 5.37 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.9Bright
25.8Bright
35.8Bright
45.8Bright
55.7Bright
65.7Bright
75.6Bright
85.6Bright
95.6Bright
105.5Bright
115.5Bright
125.5Bright
135.4Bright
145.4Bright
155.4Bright
165.3Bright
175.3Bright
185.3Bright
195.3Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.1Bright
255.1Bright
265.1Bright
275.1Bright
285.0Bright
295.0Bright
305.0Bright
315.0Bright
Planning a trip in August

Is August a good time to visit Algonquin?

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
6.5
Beach & pool
2nd-best month of the year

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

What to pack for Algonquin in August

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

In August, Algonquin sees daytime highs around 80°F and nights near 63°F. Worth packing: light clothes, rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

Sea temperature near Algonquin in August

The nearest coast averages about 71°F in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 26 mi away) is warmest in August at about 71°F and coldest in March near 36°F.

It's comfortable for a long swim from Jul 18 to Sep 8 — about 1.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar36Bracing
Apr38Bracing
May43Bracing
Jun55Bracing
Jul68Refreshing
Aug71Refreshing
Sep67Cool
Oct57Bracing
Nov47Bracing
Dec42Bracing

UV index in Algonquin 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 Algonquin peaks around June 20 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 20UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Algonquin 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 Algonquin is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (October, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 1817 µg/m³Oct 229 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar16Moderate
Apr14Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug16Moderate
Sep13Moderate
Oct9Good
Nov10Good
Dec11Good
Location & terrain

Where is Algonquin?

Algonquin sits at 42.2°N, 88.3°W, 741 ft above sea level, in United States. The nearest listed city is Lake in the Hills, 1.9 mi away.

Topography around Algonquin

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

Within 2 miles, the terrain around Algonquin has only modest variations in elevation — a maximum elevation change of 220 ft around an average of 843 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 328 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 787 ft.

The land around Algonquin is covered by trees (47%) and grassland (23%) within 2 miles, trees (41%) and grassland (26%) within 10 miles, and cropland (38%) and trees (20%) within 50 miles.

2 miles
220 ft
10 miles
328 ft
50 miles
787 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Lake in the Hills 1.9 mi · Carpentersville 3.7 mi · Cary 4.3 mi · Crystal Lake 5.6 mi · Huntley 6.8 mi · Elgin 8.7 mi · Lake Zurich 11 mi · Streamwood 11 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 Algonquin (42.1656°, -88.2943°, elevation 741 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).