Ballwin weather in May

In May, Ballwin sees average daytime highs of 75°F and overnight lows near 58°F, with 4.9 in of rain across 13.3 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 71°F in the first days to 79°F by the end. The sky is clear or mostly clear about 28% 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 Ballwin's 8th-clearest and 8th-windiest month. For the whole year in context, see Ballwin's year-round climate.

Daytime high
75°
5th warmest
Overnight low
58°
8th coldest
Rainfall
4.9 in
13.3 wet days
Daylight
14 h 06 min
4:56 AM – 7:01 PM
Cloud cover
62%
8th clearest
Wind
7 mph
8th windiest
Solar energy
5.81 kWh/m²
Travel score
6.3
out of 10

Ballwin is city in St. Louis County, Missouri, United States.

Density
1,313/km²
people per km²
Founded
1804

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 71°F in the first days to 79°F by the end.

A typical May day in Ballwin reaches about 75°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 63°F and 86°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)
17152
27153
37153
47254
57254
67254
77355
87355
97355
107456
117456
127456
137457
147557
157557
167558
177658
187658
197658
207659
217759
227760
237760
247860
257861
267861
277961
287962
297962
308062
318063

How May really feels in Ballwin

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.

Ballwin 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
Jan40° / 25°2.88.12.89.60.0
Feb45° / 28°2.57.72.810.51.0
Mar56° / 37°3.810.81.411.73.6
Apr67° / 47°4.611.30.2135.9
May75° / 58°4.913.3014.16.3
Jun84° / 67°4.011.2014.65.4
Jul88° / 70°3.410.2014.44.5
Aug86° / 68°3.09.4013.55.0
Sep80° / 60°3.27.8012.37.0
Oct68° / 48°3.58.10116.7
Nov55° / 38°3.68.30.79.93.6
Dec44° / 29°2.68.22.29.40.8

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 28% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 15% of May, with mostly cloudy or overcast conditions the remaining 58%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14357
24258
34357
44357
54258
64258
74258
84258
94258
104258
114258
124159
134258
144258
154357
164357
174258
184258
194357
204258
214258
224357
234258
244258
254258
264258
274357
284456
294357
304456
314456

Chance of precipitation in May

Any precipitation

Ballwin gets around 4.9 in of rain over 13.3 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 45% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
145
245
345
444
544
644
743
843
942
1042
1142
1242
1342
1442
1542
1642
1743
1843
1943
2043
2143
2243
2343
2443
2543
2642
2742
2841
2941
3040
3140

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 47% of days. Sticky, muggy-or-worse air turns up on roughly 17% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
168201020
267201120
365201230
462211340
561211440
659211550
758201660
856201770
955201780
1054191890
11531918100
12521819110
13521719120
14511719130
15501620140
16491520151
17481520171
18471420181
19461420191
20441420201
21431420221
22411421232
23391421242
24381421252
25361521262
26341621263
27331621273
28311721283
29291821283
30281821294
31261921304

Wind in May

Winds average 7 mph in May.

Across May, 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
17light breeze
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

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 5:12 AM to 4:45 AM, and sunset from 6:47 PM to 7:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:126:47
213.65:106:48
313.75:096:49
413.75:086:50
513.75:076:51
613.85:066:52
713.85:056:53
813.85:046:54
913.95:026:55
1013.95:016:56
1113.95:006:57
1214.04:596:58
1314.04:586:58
1414.04:576:59
1514.14:577:00
1614.14:567:01
1714.14:557:02
1814.24:547:03
1914.24:537:04
2014.24:527:05
2114.24:527:06
2214.34:517:07
2314.34:507:07
2414.34:497:08
2514.34:497:09
2614.44:487:10
2714.44:487:11
2814.44:477:11
2914.44:467:12
3014.44:467:13
3114.54:457:14

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.81 kWh/m².

For context, solar energy here swings from a low near 1.93 kWh/m² to a high of 6.42 kWh/m² in June across the year — May's 5.81 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.4Bright
35.4Bright
45.5Bright
55.5Bright
65.5Bright
75.6Bright
85.6Bright
95.6Bright
105.7Bright
115.7Bright
125.7Bright
135.8Bright
145.8Bright
155.8Bright
165.9Bright
175.9Bright
185.9Bright
195.9Bright
205.9Bright
216.0Bright
226.0Bright
236.0Bright
246.0Bright
256.0Intense
266.0Intense
276.0Intense
286.0Intense
296.0Intense
306.1Intense
316.1Intense
Planning a trip in May

Is May a good time to visit Ballwin?

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

6.3
Sightseeing
3rd-best month of the year
5.3
Beach & pool
5th-best month of the year

May is a reasonable time to visit Ballwin for sightseeing.

What to pack for Ballwin in May

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

In May, Ballwin sees daytime highs around 75°F and nights near 58°F. Worth packing: light clothes, rain gear and sun protection. About 13 days see rain.

light clothesrain gearsun protection

UV index in Ballwin 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 Ballwin peaks around June 22 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 highHighModerateJun 22UV 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 Ballwin 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 Ballwin is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodJul 1517 µg/m³Nov 127 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb10Good
Mar13Moderate
Apr10Good
May13Moderate
Jun15Moderate
Jul17Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov7Good
Dec8Good
Location & terrain

Where is Ballwin?

Ballwin sits at 38.6°N, 90.5°W, 630 ft above sea level, in United States. The nearest listed city is Manchester, 1.9 mi away.

Topography around Ballwin

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

Within 2 miles, the terrain around Ballwin has only modest variations in elevation — a maximum elevation change of 253 ft around an average of 630 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 581 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,234 ft.

The land around Ballwin is covered by trees (61%) and artificial surfaces (24%) within 2 miles, trees (66%) within 10 miles, and trees (54%) and cropland (28%) within 50 miles.

2 miles
253 ft
10 miles
581 ft
50 miles
1,234 ft
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Manchester 1.9 mi · Chesterfield 5.0 mi · Wildwood 6.2 mi · Kirkwood 7.5 mi · Creve Coeur 8.1 mi · Webster Groves 9.9 mi · Maryland Heights 11 mi · Concord 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 Ballwin (38.5951°, -90.5462°, elevation 630 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).