Clayton weather in January

In January, Clayton sees average daytime highs of 39°F and overnight lows near 24°F, with 2.8 in of precipitation across 8.2 wet days and about 9.6 hours of daylight. It is the 12th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 39°F through the month. The sky is clear or mostly clear about 28% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 18 min at the start of January to 10 hours by month's end. Set against the rest of the year, January is Clayton's 10th-clearest and 4th-windiest month. For the whole year in context, see Clayton's year-round climate.

Daytime high
39°
12th warmest
Overnight low
24°
1st coldest
Precipitation
2.8 in
8.2 wet days
Daylight
9 h 36 min
7:23 AM – 4:58 PM
Cloud cover
64%
10th clearest
Wind
8 mph
4th windiest
Solar energy
2.2 kWh/m²
Travel score
0.0
out of 10

Clayton is city in and county seat of St. Louis County, Missouri, United States.

Density
2,476/km²
people per km²
Founded
1877

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 39°F through the month.

A typical January day in Clayton reaches about 39°F in the afternoon and slips back to 24°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 24°F and 56°F. Set against its neighbours, January runs about 4°F cooler than December and about 5°F cooler than February.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
14026
24026
34025
44025
54025
63925
73925
83924
93924
103924
113924
123924
133924
143924
153924
163924
173924
183924
193924
203924
213924
223924
233924
243924
253924
264024
274024
284024
294024
304024
314025

How January really feels in Clayton

Once humidity and wind are folded in, January averages 0 days that feel above 90°F and 31 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
31
wind chill below the day's low

The story in January is cold — wind chill drags the overnight "feels like" below the raw low.

Clayton weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 24°2.88.22.99.60.0
Feb44° / 28°2.57.72.810.50.8
Mar55° / 37°3.710.51.411.73.5
Apr66° / 47°4.611.20.2135.8
May75° / 58°5.013.5014.16.2
Jun84° / 67°4.211014.65.4
Jul87° / 70°3.49.9014.44.7
Aug86° / 68°2.99.2013.55.2
Sep79° / 60°3.37.6012.37.1
Oct67° / 48°3.48.40.1116.6
Nov54° / 37°3.68.60.89.93.4
Dec43° / 29°2.68.22.29.30.6

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

Beyond those clear spells, partly cloudy skies cover about 12% of January, with mostly cloudy or overcast conditions the remaining 60%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13763
23763
33763
43862
53961
63961
73961
83961
93961
103961
113961
123961
133961
143961
153961
163961
174060
184060
194060
204060
214159
224258
234258
244258
254258
264258
274357
284357
294357
304258
314159

Chance of precipitation in January

Any precipitationSnow

Clayton gets around 2.8 in of rain and snow over 8.2 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 26% and peaks near 28% on the wettest days, and about 3 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1258
2269
3269
4279
5279
6289
72810
82810
92810
102810
112810
122810
132810
142810
152810
16279
17279
18269
19269
20259
21259
22259
23249
24249
25249
26249
27239
28239
29239
30239
31239

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the dry band about 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3982
4982
5982
6982
7991
8991
9991
10991
11991
12991
13991
14991
151000
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000
311000

Wind in January

Winds average 8 mph in January.

Across January, daily wind ranges from about 8 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
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light breeze

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 18 min at the start of January to 10 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 42 minutes over January. Sunrise moves from 7:24 AM to 7:15 AM, and sunset from 4:45 PM to 5:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.37:244:45
29.47:244:45
39.47:244:46
49.47:254:47
59.47:254:48
69.47:254:49
79.47:254:50
89.47:254:50
99.47:254:51
109.57:244:52
119.57:244:53
129.57:244:54
139.57:244:55
149.57:244:56
159.67:244:57
169.67:234:58
179.67:234:59
189.67:235:00
199.67:225:01
209.77:225:02
219.77:215:03
229.77:215:04
239.77:205:05
249.87:205:06
259.87:195:07
269.87:195:08
279.97:185:10
289.97:175:11
299.97:175:12
309.97:165:13
3110.07:155:14

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.2 kWh/m².

For context, solar energy here swings from a low near 1.9 kWh/m² to a high of 6.43 kWh/m² in June across the year — January's 2.2 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.9Dim
21.9Dim
32.0Dim
42.0Dim
52.0Dim
62.0Dim
72.0Moderate
82.0Moderate
92.0Moderate
102.0Moderate
112.1Moderate
122.1Moderate
132.1Moderate
142.1Moderate
152.2Moderate
162.2Moderate
172.2Moderate
182.2Moderate
192.3Moderate
202.3Moderate
212.3Moderate
222.4Moderate
232.4Moderate
242.4Moderate
252.4Moderate
262.5Moderate
272.5Moderate
282.5Moderate
292.6Moderate
302.6Moderate
312.6Moderate
Planning a trip in January

Is January a good time to visit Clayton?

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

0.0
Sightseeing
12th-best month of the year
0.0
Beach & pool
10th-best month of the year

January is a weaker month for outdoor sightseeing in Clayton.

What to pack for Clayton in January

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

In January, Clayton sees daytime highs around 39°F and nights near 24°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 8 days see rain.

a warm layera heavy coatrain gear

UV index in Clayton in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Clayton peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 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 23UV 9Jan 1UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep7High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Clayton in January

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Clayton 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 Clayton?

Clayton sits at 38.6°N, 90.3°W, 568 ft above sea level, in United States. The nearest listed city is University City, 1.2 mi away.

Topography around Clayton

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

Within 2 miles, the terrain around Clayton has only modest variations in elevation — a maximum elevation change of 194 ft around an average of 541 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 459 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 994 ft.

The land around Clayton is covered by trees (48%) and artificial surfaces (44%) within 2 miles, trees (44%) and artificial surfaces (36%) within 10 miles, and trees (48%) and cropland (37%) within 50 miles.

2 miles
194 ft
10 miles
459 ft
50 miles
994 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: University City 1.2 mi · Webster Groves 3.7 mi · Overland 4.3 mi · Creve Coeur 5.6 mi · Kirkwood 6.2 mi · Affton 6.2 mi · St. Louis 6.8 mi · Ferguson 6.8 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 Clayton (38.6425°, -90.3237°, elevation 568 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).