Mount Vernon weather in July

In July, Mount Vernon sees average daytime highs of 88°F and overnight lows near 71°F, with 3.4 in of rain across 10.3 wet days and about 14.4 hours of daylight. It is the 1st-warmest and 7th-wettest month of the year here.

Day-to-day highs hold fairly steady near 88°F through the month. The sky is clear or mostly clear about 38% of the time in July, and the air most often feels oppressive.

Daylight stretches from about 14 h 36 min at the start of July to 14 hours by month's end. Set against the rest of the year, July is Mount Vernon's 4th-clearest and 11th-windiest month. For the whole year in context, see Mount Vernon's year-round climate.

Daytime high
88°
1st warmest
Overnight low
71°
12th coldest
Rainfall
3.4 in
10.3 wet days
Daylight
14 h 24 min
4:48 AM – 7:14 PM
Cloud cover
53%
4th clearest
Wind
6 mph
11th windiest
Solar energy
6.4 kWh/m²
Travel score
4.5
out of 10

Mount Vernon is city located near the center of Jefferson County, Illinois, United States.

Density
396/km²
people per km²
Founded
1817

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in July

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 88°F through the month.

A typical July day in Mount Vernon reaches about 88°F in the afternoon and slips back to 71°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 81°F and 94°F. Set against its neighbours, July runs about 3°F warmer than June and about 1°F warmer than August.

60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18771
28771
38771
48771
58871
68871
78871
88871
98871
108871
118872
128872
138872
148872
158872
168872
178872
188872
198872
208872
218872
228871
238871
248871
258871
268871
278871
288771
298771
308771
318771

How July really feels in Mount Vernon

Once humidity and wind are folded in, July averages 29 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
29
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in July is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Mount Vernon weather by month

How July compares with the rest of the year at a glance. July is the 1st-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan41° / 26°3.392.69.60.0
Feb45° / 30°2.98.42.710.51.1
Mar56° / 38°4.110.81.211.73.7
Apr67° / 49°5.211.30.1135.9
May76° / 59°5.112.90146.3
Jun85° / 68°3.910.4014.65.2
Jul88° / 71°3.410.3014.44.5
Aug86° / 69°2.88.4013.55.2
Sep80° / 61°3.07.3012.37.0
Oct68° / 49°3.67.90116.8
Nov55° / 39°3.88.80.69.93.6
Dec44° / 31°3.28.629.40.9

Cloud cover in July

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in July.

Beyond those clear spells, partly cloudy skies cover about 19% of July, with mostly cloudy or overcast conditions the remaining 43%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15644
25743
35743
45743
55743
65743
75743
85743
95743
105743
115842
125743
135743
145743
155743
165743
175644
185644
195644
205644
215644
225644
235743
245743
255743
265842
275842
285842
295941
305941
315941

Chance of precipitation in July

Any precipitation

Mount Vernon gets around 3.4 in of rain over 10.3 wet days in July. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 33% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
337
437
536
636
736
835
934
1034
1133
1233
1332
1432
1531
1631
1731
1831
1931
2031
2131
2231
2331
2431
2531
2631
2731
2831
2931
3031
3131

Humidity in July

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, July lands in the oppressive band about 37% of days. Sticky, muggy-or-worse air turns up on roughly 67% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
16122034280
25122034290
35112034290
45112033300
55112033311
64112032321
74102032331
84102032341
94102031351
10391931361
11391931371
12391930381
13391830401
14391829402
15291728412
16291727422
172101727422
182101726422
192111725432
202111725433
212121725423
222121725423
232121725413
242131725412
252131825392
262131926382
272131926372
282132027362
292132127352
302132128342
313132129331

Wind in July

Winds average 6 mph in July.

Across July, daily wind ranges from about 5 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
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in July

DaylightNight

Daylight runs from about 14 h 36 min at the start of July to 14 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 36 minutes over July. Sunrise moves from 4:40 AM to 5:00 AM, and sunset from 7:18 PM to 7:03 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.64:407:18
214.64:407:18
314.64:417:18
414.64:417:18
514.64:427:18
614.64:427:17
714.64:437:17
814.64:437:17
914.54:447:17
1014.54:457:16
1114.54:457:16
1214.54:467:16
1314.54:467:15
1414.54:477:15
1514.44:487:14
1614.44:487:14
1714.44:497:13
1814.44:507:13
1914.44:517:12
2014.34:517:12
2114.34:527:11
2214.34:537:10
2314.34:547:10
2414.24:557:09
2514.24:557:08
2614.24:567:07
2714.24:577:07
2814.14:587:06
2914.14:597:05
3014.15:007:04
3114.05:007:03

Solar energy in July

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in July, about 6.4 kWh/m².

For context, solar energy here swings from a low near 1.9 kWh/m² to a high of 6.46 kWh/m² in June across the year — July's 6.4 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.5Intense
26.5Intense
36.5Intense
46.5Intense
56.5Intense
66.5Intense
76.5Intense
86.5Intense
96.5Intense
106.5Intense
116.5Intense
126.5Intense
136.5Intense
146.5Intense
156.5Intense
166.5Intense
176.5Intense
186.4Intense
196.4Intense
206.4Intense
216.4Intense
226.4Intense
236.3Intense
246.3Intense
256.3Intense
266.3Intense
276.3Intense
286.3Intense
296.2Intense
306.2Intense
316.2Intense
Planning a trip in July

Is July a good time to visit Mount Vernon?

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

4.5
Sightseeing
7th-best month of the year
6.7
Beach & pool
4th-best month of the year

July is a reasonable time to visit Mount Vernon for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Mount Vernon in July

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

In July, Mount Vernon sees daytime highs around 88°F and nights near 71°F. Pack light clothes and sun protection. Worth having: rain gear. About 10 days see rain.

light clothessun protectionrain gear

UV index in Mount Vernon in July

LowModerateHighVery highExtreme

Clear-sky midday UV in July peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Mount Vernon peaks around July 10 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 10UV 9Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5High
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Mount Vernon in July

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Mount Vernon is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1417 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar12Good
Apr11Good
May14Moderate
Jun16Moderate
Jul18Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Mount Vernon?

Mount Vernon sits at 38.3°N, 88.9°W, 512 ft above sea level, in United States. The nearest listed city is Marion, 40 mi away.

Topography around Mount Vernon

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

Within 2 miles, the terrain around Mount Vernon has only modest variations in elevation — a maximum elevation change of 174 ft around an average of 489 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 279 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 499 ft.

The land around Mount Vernon is covered by trees (49%) within 2 miles, trees (42%) and cropland (37%) within 10 miles, and cropland (59%) and trees (31%) within 50 miles.

2 miles
174 ft
10 miles
279 ft
50 miles
499 ft
treesgrasslandcroplandartificial surfaceswater
July weather nearby: Marion 40 mi · Carbondale 44 mi · O'Fallon 58 mi · Belleville 60 mi · Fairview Heights 62 mi · Collinsville 63 mi · Edwardsville 66 mi · East Saint Louis 71 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 Mount Vernon (38.3173°, -88.9031°, elevation 512 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).