Alton weather in July

In July, Alton sees average daytime highs of 87°F and overnight lows near 70°F, with 3.2 in of rain across 9.5 wet days and about 14.4 hours of daylight. It is the 1st-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 87°F through the month. The sky is clear or mostly clear about 40% of the time in July, and the air most often feels oppressive.

Daylight stretches from about 14 h 42 min at the start of July to 14 h 06 min by month's end. Set against the rest of the year, July is Alton's 4th-clearest and 11th-windiest month. For the whole year in context, see Alton's year-round climate.

Daytime high
87°
1st warmest
Overnight low
70°
12th coldest
Rainfall
3.2 in
9.5 wet days
Daylight
14 h 30 min
4:52 AM – 7:21 PM
Cloud cover
52%
4th clearest
Wind
5 mph
11th windiest
Solar energy
6.42 kWh/m²
Travel score
5.0
out of 10

Alton is city in Madison County, Illinois, United States.

Density
623/km²
people per km²
Founded
1818

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 87°F through the month.

A typical July day in Alton reaches about 87°F in the afternoon and slips back to 70°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 79°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)
18669
28669
38669
48670
58670
68670
78770
88770
98770
108770
118770
128770
138770
148771
158771
168771
178771
188771
198771
208770
218770
228770
238770
248770
258770
268770
278670
288669
298669
308669
318669

How July really feels in Alton

Once humidity and wind are folded in, July averages 15 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
15
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.

Alton weather by month

How July compares with the rest of the year at a glance. July is the 1st-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan38° / 24°2.68.23.29.60.0
Feb43° / 27°2.47.6310.50.6
Mar54° / 36°3.610.41.511.73.3
Apr66° / 47°4.611.60.2135.7
May75° / 58°5.013.5014.16.2
Jun83° / 67°4.010.9014.75.6
Jul87° / 70°3.29.5014.45.0
Aug85° / 67°2.98.9013.55.5
Sep79° / 59°3.37.5012.37.2
Oct67° / 48°3.38.40.1116.5
Nov53° / 37°3.68.60.79.93.2
Dec42° / 28°2.48.12.39.30.4

Cloud cover in July

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% 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 41%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15842
25842
35842
45941
55941
65941
75941
86040
96040
106040
116040
126040
136040
146040
155842
165842
175842
185842
195743
205743
215743
225842
235842
245842
255842
265842
275842
285941
295941
305941
315941

Chance of precipitation in July

Any precipitation

Alton gets around 3.2 in of rain over 9.5 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 30% and peaks near 34% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
134
234
334
433
533
633
732
832
931
1030
1130
1229
1329
1429
1528
1628
1728
1828
1928
2028
2128
2228
2329
2429
2529
2630
2730
2830
2930
3030
3130

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 35% of days. Sticky, muggy-or-worse air turns up on roughly 66% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
15132132291
25132031301
35132031301
44132031311
54122030322
64122030322
74122030332
83111931342
93111931342
103111931343
113101931353
123101830363
132101830363
142101830373
152101829383
162101828383
172101828384
182101827393
192111827393
202111926393
212111926393
222121926393
232121925393
242122025383
252132025372
262132126362
272132126352
282132227342
292132227332
303132228321
313132229311

Wind in July

Winds average 5 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
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in July

DaylightNight

Daylight runs from about 14 h 42 min at the start of July to 14 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 36 minutes over July. Sunrise moves from 4:43 AM to 5:04 AM, and sunset from 7:25 PM to 7:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.74:437:25
214.74:447:25
314.74:447:25
414.74:457:25
514.74:457:24
614.64:467:24
714.64:467:24
814.64:477:24
914.64:477:24
1014.64:487:23
1114.64:497:23
1214.64:497:22
1314.54:507:22
1414.54:517:22
1514.54:517:21
1614.54:527:21
1714.54:537:20
1814.44:547:20
1914.44:547:19
2014.44:557:18
2114.44:567:18
2214.34:577:17
2314.34:577:16
2414.34:587:15
2514.34:597:15
2614.25:007:14
2714.25:017:13
2814.25:027:12
2914.15:037:11
3014.15:037:10
3114.15:047:09

Solar energy in July

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in July, about 6.42 kWh/m².

For context, solar energy here swings from a low near 1.88 kWh/m² to a high of 6.44 kWh/m² in June across the year — July's 6.42 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.6Intense
26.6Intense
36.6Intense
46.6Intense
56.6Intense
66.6Intense
76.6Intense
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
286.2Intense
296.2Intense
306.2Intense
316.2Intense
Planning a trip in July

Hazard calendar for Alton

In seasonPeak

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

Alton 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 July a good time to visit Alton?

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

5.0
Sightseeing
7th-best month of the year
7.0
Beach & pool
2nd-best month of the year

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

What to pack for Alton in July

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

In July, Alton sees daytime highs around 87°F and nights near 70°F. Pack light clothes and sun protection. Worth having: rain gear. About 10 days see rain.

light clothessun protectionrain gear

UV index in Alton 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 Alton peaks around June 21 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJun 21UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Alton 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 Alton is worst in August — around 18 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodAug 1018 µg/m³Oct 228 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar13Moderate
Apr11Good
May14Moderate
Jun16Moderate
Jul18Moderate
Aug18Moderate
Sep13Moderate
Oct8Good
Nov9Good
Dec10Good
Location & terrain

Where is Alton?

Alton sits at 38.9°N, 90.2°W, 492 ft above sea level, in United States. The nearest listed city is Upper Alton, 2.5 mi away.

Topography around Alton

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

Within 2 miles, the terrain around Alton has only modest variations in elevation — a maximum elevation change of 256 ft around an average of 476 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 636 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 801 ft.

The land around Alton is covered by trees (38%) and water (28%) within 2 miles, trees (41%) and cropland (28%) within 10 miles, and cropland (47%) and trees (39%) within 50 miles.

2 miles
256 ft
10 miles
636 ft
50 miles
801 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
July weather nearby: Upper Alton 2.5 mi · Godfrey 4.3 mi · Old Jamestown 6.8 mi · Spanish Lake 7.5 mi · Florissant 9.9 mi · Ferguson 12 mi · Hazelwood 13 mi · Granite City 13 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 Alton (38.8906°, -90.1843°, elevation 492 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).