Collinsville weather in May

In May, Collinsville sees average daytime highs of 76°F and overnight lows near 58°F, with 5.2 in of rain across 13.5 wet days and about 14.1 hours of daylight. It is the 5th-warmest and 1st-wettest month of the year here.

Highs climb over the month, from about 72°F in the first days to 80°F by the end. The sky is clear or mostly clear about 27% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 36 min at the start of May to 14 h 30 min by month's end. Set against the rest of the year, May is Collinsville's 8th-clearest and 8th-windiest month. For the whole year in context, see Collinsville's year-round climate.

Daytime high
76°
5th warmest
Overnight low
58°
8th coldest
Rainfall
5.2 in
13.5 wet days
Daylight
14 h 06 min
4:53 AM – 6:59 PM
Cloud cover
62%
8th clearest
Wind
7 mph
8th windiest
Solar energy
5.82 kWh/m²
Travel score
6.2
out of 10

Collinsville is city in Illinois, United States.

Density
643/km²
people per km²

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 72°F in the first days to 80°F by the end.

A typical May day in Collinsville reaches about 76°F in the afternoon and slips back to 58°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 87°F. Set against its neighbours, May runs about 9°F warmer than April and about 9°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
17153
27153
37254
47254
57354
67355
77355
87355
97456
107456
117456
127557
137557
147557
157658
167658
177658
187659
197759
207759
217760
227860
237860
247861
257961
267962
277962
288062
298063
308063
318063

How May really feels in Collinsville

Once humidity and wind are folded in, May 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

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Collinsville weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 24°2.98.32.99.60.0
Feb44° / 28°2.57.62.710.50.8
Mar55° / 37°3.710.61.411.73.5
Apr67° / 47°4.811.70.1135.8
May76° / 58°5.213.5014.16.2
Jun84° / 67°4.210.8014.65.3
Jul87° / 70°3.39.6014.44.7
Aug86° / 68°3.08.7013.55.3
Sep80° / 60°3.27.7012.37.0
Oct67° / 48°3.58.30116.6
Nov54° / 38°3.78.70.79.93.4
Dec43° / 29°2.68.42.39.30.6

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 16% of May, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14258
24357
34258
44258
54357
64258
74258
84258
94357
104357
114357
124456
134357
144357
154357
164357
174357
184357
194258
204357
214258
224258
234258
244258
254357
264258
274357
284357
294357
304456
314456

Chance of precipitation in May

Any precipitation

Collinsville gets around 5.2 in of rain over 13.5 wet days in May, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 43% and peaks near 47% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
147
247
346
446
546
645
745
845
944
1044
1143
1243
1343
1443
1542
1642
1743
1843
1943
2043
2143
2243
2342
2442
2542
2641
2741
2840
2940
3039
3139

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 50% of days. Sticky, muggy-or-worse air turns up on roughly 14% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
170181020
268191120
367191220
465191330
564191430
662191540
760191650
859191750
958181860
1056181970
1156172070
1255172080
1354162190
14531621100
15521621110
16521521120
17501521140
18491521150
19481421160
20461421180
21451421191
22431521211
23411521221
24401621231
25381621241
26371720251
27351820261
28341820271
29321920281
30312020282
31302019292

Wind in May

Winds average 7 mph in May.

Across May, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
107light breeze
117light breeze
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 36 min at the start of May to 14 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 54 minutes over May. Sunrise moves from 5:09 AM to 4:43 AM, and sunset from 6:45 PM to 7:12 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:096:45
213.65:086:46
313.75:076:47
413.75:066:48
513.75:056:49
613.85:036:50
713.85:026:51
813.85:016:52
913.95:006:53
1013.94:596:54
1113.94:586:55
1214.04:576:55
1314.04:566:56
1414.04:556:57
1514.14:546:58
1614.14:536:59
1714.14:527:00
1814.24:527:01
1914.24:517:02
2014.24:507:03
2114.24:497:04
2214.34:487:04
2314.34:487:05
2414.34:477:06
2514.34:467:07
2614.44:467:08
2714.44:457:09
2814.44:457:09
2914.44:447:10
3014.54:447:11
3114.54:437:12

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.82 kWh/m².

For context, solar energy here swings from a low near 1.88 kWh/m² to a high of 6.46 kWh/m² in June across the year — May's 5.82 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.5Bright
45.5Bright
55.5Bright
65.6Bright
75.6Bright
85.6Bright
95.7Bright
105.7Bright
115.7Bright
125.8Bright
135.8Bright
145.8Bright
155.8Bright
165.9Bright
175.9Bright
185.9Bright
195.9Bright
206.0Bright
216.0Bright
226.0Bright
236.0Intense
246.0Intense
256.0Intense
266.0Intense
276.0Intense
286.1Intense
296.1Intense
306.1Intense
316.1Intense
Planning a trip in May

Is May a good time to visit Collinsville?

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

6.2
Sightseeing
3rd-best month of the year
5.3
Beach & pool
5th-best month of the year

May is a reasonable time to visit Collinsville for sightseeing.

What to pack for Collinsville in May

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

In May, Collinsville sees daytime highs around 76°F and nights near 58°F. Worth packing: light clothes, rain gear and sun protection. About 14 days see rain.

light clothesrain gearsun protection

UV index in Collinsville in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May 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 Collinsville 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 Collinsville in May

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Collinsville 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 Collinsville?

Collinsville sits at 38.7°N, 90.0°W, 561 ft above sea level, in United States. The nearest listed city is Fairview Heights, 5.6 mi away.

Topography around Collinsville

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

Within 2 miles, the terrain around Collinsville has only modest variations in elevation — a maximum elevation change of 190 ft around an average of 531 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 299 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 866 ft.

The land around Collinsville is covered by trees (66%) within 2 miles, trees (40%) and cropland (28%) within 10 miles, and cropland (49%) and trees (38%) within 50 miles.

2 miles
190 ft
10 miles
299 ft
50 miles
866 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Fairview Heights 5.6 mi · O'Fallon 6.8 mi · Granite City 9.3 mi · East Saint Louis 9.3 mi · Edwardsville 9.9 mi · Belleville 11 mi · St. Louis 12 mi · Spanish Lake 15 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 Collinsville (38.6703°, -89.9845°, elevation 561 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).