Quincy weather in August

In August, Quincy sees average daytime highs of 84°F and overnight lows near 66°F, with 3.2 in of rain across 8.4 wet days and about 13.6 hours of daylight. It is the 2nd-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 84°F through the month. The sky is clear or mostly clear about 42% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 h 06 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Quincy's 2nd-clearest and 12th-windiest month. For the whole year in context, see Quincy's year-round climate.

Daytime high
84°
2nd warmest
Overnight low
66°
11th coldest
Rainfall
3.2 in
8.4 wet days
Daylight
13 h 36 min
5:22 AM – 6:57 PM
Cloud cover
50%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
5.72 kWh/m²
Travel score
5.7
out of 10

Quincy is county seat of Adams County, Illinois, United States.

Density
988/km²
people per km²
Founded
1819

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 84°F through the month.

A typical August day in Quincy reaches about 84°F in the afternoon and slips back to 66°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 77°F and 93°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)
18568
28568
38568
48567
58567
68567
78567
88567
98567
108567
118567
128567
138567
148466
158466
168466
178466
188466
198466
208466
218466
228466
238466
248466
258465
268465
278465
288365
298365
308364
318364

How August really feels in Quincy

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.

Quincy 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
Jan36° / 20°1.97.24.29.50.0
Feb40° / 24°2.273.210.40.2
Mar52° / 34°2.99.61.811.72.8
Apr64° / 45°4.411.30.3135.4
May74° / 55°4.612.7014.26.3
Jun83° / 65°4.010.5014.85.8
Jul86° / 69°3.49014.55.2
Aug84° / 66°3.28.4013.65.7
Sep78° / 58°3.37.4012.37.3
Oct65° / 46°2.88.50.210.96.2
Nov51° / 35°2.97.60.99.82.8
Dec40° / 25°2.16.92.89.20.2

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 19% of August, with mostly cloudy or overcast conditions the remaining 39%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16238
26238
36238
46238
56238
66238
76337
86238
96238
106238
116238
126139
136139
146139
156139
166040
176040
186040
196040
205941
215941
225941
235941
246040
256040
266040
276139
286139
296139
306337
316337

Chance of precipitation in August

Any precipitation

Quincy gets around 3.2 in of rain over 8.4 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 27% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
129
228
328
428
527
627
727
827
927
1027
1127
1228
1328
1428
1528
1628
1728
1828
1928
2028
2128
2228
2328
2428
2527
2627
2726
2826
2925
3025
3125

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 31% of days. Sticky, muggy-or-worse air turns up on roughly 51% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
14162627252
24162628242
34162628242
44162729231
54162729231
65162729221
75152730221
85152730211
96152730211
106152730211
117152730201
127152730201
137152630201
147162630191
157162630191
168162630191
178162631191
188162531191
198162532191
208162532191
218162432191
228162433191
238162433191
248162433191
258172333190
268172333180
279172332180
2810182332170
2910182332160
3011192331150
3113192331150

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 6 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
306calm
316calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 06 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 66 minutes over August. Sunrise moves from 5:08 AM to 5:37 AM, and sunset from 7:16 PM to 6:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.15:087:16
214.15:097:15
314.15:107:14
414.05:107:12
514.05:117:11
614.05:127:10
713.95:137:09
813.95:147:08
913.95:157:07
1013.85:167:05
1113.85:177:04
1213.75:187:03
1313.75:197:01
1413.75:207:00
1513.65:216:59
1613.65:226:57
1713.55:236:56
1813.55:246:55
1913.55:256:53
2013.45:266:52
2113.45:276:50
2213.35:286:49
2313.35:296:47
2413.35:306:46
2513.25:316:44
2613.25:326:43
2713.15:336:41
2813.15:346:39
2913.15:356:38
3013.05:366:36
3113.05:376:35

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.72 kWh/m².

For context, solar energy here swings from a low near 1.84 kWh/m² to a high of 6.44 kWh/m² in June across the year — August's 5.72 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.1Intense
46.1Intense
56.0Intense
66.0Intense
76.0Bright
86.0Bright
95.9Bright
105.9Bright
115.9Bright
125.8Bright
135.8Bright
145.8Bright
155.7Bright
165.7Bright
175.7Bright
185.7Bright
195.6Bright
205.6Bright
215.6Bright
225.5Bright
235.5Bright
245.5Bright
255.5Bright
265.4Bright
275.4Bright
285.4Bright
295.4Bright
305.3Bright
315.3Bright
Planning a trip in August

Hazard calendar for Quincy

In seasonPeak

In August, Quincy sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Quincy sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is August a good time to visit Quincy?

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

5.7
Sightseeing
5th-best month of the year
7.4
Beach & pool
1st-best month of the year

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

What to pack for Quincy in August

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

In August, Quincy sees daytime highs around 84°F and nights near 66°F. Pack light clothes. Worth having: rain gear and sun protection. About 8 days see rain.

light clothesrain gearsun protection

UV index in Quincy in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Quincy peaks around June 20 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 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJun 20UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun10Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Quincy 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 Quincy is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (October, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodJul 1716 µg/m³Oct 237 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Moderate
Mar12Good
Apr10Good
May13Moderate
Jun14Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov7Good
Dec8Good
Location & terrain

Where is Quincy?

Quincy sits at 39.9°N, 91.4°W, 568 ft above sea level, in United States. The nearest listed city is Hannibal, 16 mi away.

Topography around Quincy

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

Within 2 miles, the terrain around Quincy has only modest variations in elevation — a maximum elevation change of 230 ft around an average of 551 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 702 ft.

The land around Quincy is covered by trees (35%) and artificial surfaces (29%) within 2 miles, cropland (53%) and trees (26%) within 10 miles, and cropland (53%) and trees (32%) within 50 miles.

2 miles
230 ft
10 miles
328 ft
50 miles
702 ft
treesgrasslandcroplandartificial surfaceswater
August weather nearby: Hannibal 16 mi · Macomb 53 mi · Burlington 62 mi · Jacksonville 64 mi · Kirksville 65 mi · Wentzville 83 mi · Columbia 84 mi · O'Fallon 86 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 Quincy (39.9356°, -91.4099°, elevation 568 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).