Affton weather in May

In May, Affton sees average daytime highs of 76°F and overnight lows near 58°F, with 5.0 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 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 Affton's 8th-clearest and 8th-windiest month. For the whole year in context, see Affton's year-round climate.

Daytime high
76°
5th warmest
Overnight low
58°
8th coldest
Rainfall
5.0 in
13.3 wet days
Daylight
14 h 06 min
4:55 AM – 7:00 PM
Cloud cover
62%
8th clearest
Wind
7 mph
8th windiest
Solar energy
5.82 kWh/m²
Travel score
6.3
out of 10

Affton is Unincorporated community in Missouri, U.S..

Density
1,642/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 Affton 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 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)
17153
27153
37254
47254
57355
67355
77355
87356
97456
107456
117456
127557
137557
147558
157658
167658
177658
187659
197759
207760
217760
227860
237861
247861
257961
267962
277962
288062
298063
308063
318063

How May really feels in Affton

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.

Affton 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°2.98.32.89.60.0
Feb45° / 28°2.57.52.710.51.0
Mar56° / 37°3.810.71.211.73.7
Apr67° / 48°4.711.30.2135.9
May76° / 58°5.013.3014.16.3
Jun84° / 67°4.111014.65.3
Jul88° / 71°3.410014.44.6
Aug86° / 68°2.99.3013.55.1
Sep80° / 60°3.27.7012.37.0
Oct68° / 48°3.58.20116.7
Nov55° / 38°3.78.60.79.93.6
Dec44° / 29°2.78.32.29.40.8

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
24258
34258
44159
54258
64258
74258
84258
94258
104258
114159
124357
134357
144357
154258
164357
174357
184357
194258
204357
214357
224357
234357
244357
254357
264357
274456
284456
294456
304555
314555

Chance of precipitation in May

Any precipitation

Affton gets around 5.0 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
445
544
644
744
843
943
1043
1143
1243
1342
1442
1542
1643
1743
1843
1943
2043
2143
2243
2342
2442
2542
2641
2741
2841
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 49% of days. Sticky, muggy-or-worse air turns up on roughly 16% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
170181020
268191120
366191230
464191430
562191540
660191650
759191750
857191860
957181870
1055181980
1154172090
12531720100
13531620110
14511621120
15511521130
16501521141
17491421161
18481421171
19471421181
20451421191
21441421211
22421421221
23401421232
24391421242
25371522242
26361522252
27341622263
28321722263
29311722273
30291822273
31281922283

Wind in May

Winds average 7 mph in May.

Across May, daily wind ranges from about 6 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
67light breeze
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
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 5:11 AM to 4:45 AM, and sunset from 6:46 PM to 7:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:116:46
213.65:106:47
313.75:096:48
413.75:076:49
513.75:066:50
613.85:056:51
713.85:046:52
813.85:036:53
913.95:026:54
1013.95:016:55
1113.95:006:56
1214.04:596:57
1314.04:586:58
1414.04:576:58
1514.14:566:59
1614.14:557:00
1714.14:547:01
1814.14:537:02
1914.24:527:03
2014.24:527:04
2114.24:517:05
2214.34:507:06
2314.34:497:06
2414.34:497:07
2514.34:487:08
2614.44:477:09
2714.44:477:10
2814.44:467:10
2914.44:467:11
3014.44:457:12
3114.54:457:13

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 1.92 kWh/m² to a high of 6.45 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
35.4Bright
45.5Bright
55.5Bright
65.5Bright
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
286.0Intense
296.1Intense
306.1Intense
316.1Intense
Planning a trip in May

Is May a good time to visit Affton?

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
5.4
Beach & pool
5th-best month of the year

May is a reasonable time to visit Affton for sightseeing.

What to pack for Affton in May

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

In May, Affton sees daytime highs around 76°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 Affton 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 Affton 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 Affton 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 Affton is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1418 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb12Good
Mar12Good
Apr11Good
May14Moderate
Jun16Moderate
Jul18Moderate
Aug15Moderate
Sep12Moderate
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Affton?

Affton sits at 38.6°N, 90.3°W, 617 ft above sea level, in United States. The nearest listed city is Concord, 2.5 mi away.

Topography around Affton

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

Within 2 miles, the terrain around Affton has only modest variations in elevation — a maximum elevation change of 226 ft around an average of 538 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 604 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,024 ft.

The land around Affton is covered by trees (51%) and artificial surfaces (35%) within 2 miles, trees (47%) and artificial surfaces (28%) within 10 miles, and trees (50%) and cropland (34%) within 50 miles.

2 miles
226 ft
10 miles
604 ft
50 miles
1,024 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Concord 2.5 mi · Mehlville 3.1 mi · Lemay 3.1 mi · Webster Groves 3.1 mi · Kirkwood 4.3 mi · Oakville 5.6 mi · Clayton 6.2 mi · University City 7.5 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 Affton (38.5506°, -90.3332°, elevation 617 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).