Trenton weather in January

In January, Trenton sees average daytime highs of 40°F and overnight lows near 27°F, with 3.3 in of precipitation across 9.3 wet days and about 9.5 hours of daylight. It is the 12th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 40°F through the month. The sky is clear or mostly clear about 30% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 12 min at the start of January to 9 h 54 min by month's end. Set against the rest of the year, January is Trenton's 8th-clearest and 2nd-windiest month. For the whole year in context, see Trenton's year-round climate.

Daytime high
40°
12th warmest
Overnight low
27°
1st coldest
Precipitation
3.3 in
9.3 wet days
Daylight
9 h 24 min
7:25 AM – 4:51 PM
Cloud cover
61%
8th clearest
Wind
8 mph
2nd windiest
Solar energy
2.14 kWh/m²
Travel score
0.0
out of 10

Trenton is capital city of the U.S. state of New Jersey and seat of Mercer County.

Density
4,218/km²
people per km²
Founded
1719

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 40°F through the month.

A typical January day in Trenton reaches about 40°F in the afternoon and slips back to 27°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 27°F and 54°F. Set against its neighbours, January runs about 5°F cooler than December and about 3°F cooler than February.

20°40°60°151015202531
Avg high (°F)Avg low (°F)
14229
24229
34228
44128
54128
64128
74128
84128
94128
104028
114027
124027
134027
144027
154027
164026
174026
183926
193926
203926
213926
223926
233926
243926
253926
264026
274026
284026
294026
304026
314026

How January really feels in Trenton

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.

Trenton 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
Jan40° / 27°3.39.33.89.50.0
Feb43° / 28°3.08.83.410.40.5
Mar51° / 35°4.210.32.611.72.5
Apr63° / 45°3.610.60.3135.2
May72° / 54°3.511.4014.26.4
Jun81° / 63°4.010.8014.86.0
Jul86° / 69°4.211.3014.64.9
Aug84° / 67°4.010.4013.65.6
Sep77° / 60°4.09.2012.36.9
Oct65° / 49°3.68.40.110.96.2
Nov54° / 39°2.97.80.39.83.5
Dec45° / 31°4.09.41.99.21.0

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 14% of January, with mostly cloudy or overcast conditions the remaining 55%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14852
24852
34852
44753
54753
64753
74654
84654
94555
104555
114555
124555
134456
144456
154456
164456
174357
184357
194357
204357
214357
224357
234456
244456
254456
264456
274555
284555
294555
304555
314654

Chance of precipitation in January

Any precipitationSnow

Trenton gets around 3.3 in of rain and snow over 9.3 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 30% and peaks near 33% on the wettest days, and about 4 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1319
23110
33110
43210
53211
63211
73311
83312
93312
103312
113312
123313
133213
143213
153213
163113
173113
183013
193013
202913
212813
222813
232713
242713
252712
262612
272612
282612
292612
302712
312712

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 (%)
1991
2991
3991
4991
5991
6991
7991
8991
9991
10991
11991
12991
13991
14991
15991
16991
17991
18991
19991
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 12 min at the start of January to 9 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 42 minutes over January. Sunrise moves from 7:27 AM to 7:16 AM, and sunset from 4:38 PM to 5:08 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.27:274:38
29.27:274:38
39.27:274:39
49.27:274:40
59.27:274:41
69.27:274:42
79.37:274:43
89.37:274:43
99.37:274:44
109.37:274:45
119.37:274:46
129.37:264:47
139.47:264:48
149.47:264:49
159.47:264:50
169.47:254:51
179.57:254:52
189.57:254:53
199.57:244:54
209.57:244:56
219.67:234:57
229.67:234:58
239.67:224:59
249.67:215:00
259.77:215:01
269.77:205:02
279.77:205:03
289.87:195:05
299.87:185:06
309.87:175:07
319.97:165:08

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.14 kWh/m².

For context, solar energy here swings from a low near 1.8 kWh/m² to a high of 6.01 kWh/m² in June across the year — January's 2.14 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.9Dim
21.9Dim
31.9Dim
41.9Dim
51.9Dim
61.9Dim
71.9Dim
81.9Dim
92.0Dim
102.0Dim
112.0Moderate
122.0Moderate
132.0Moderate
142.1Moderate
152.1Moderate
162.1Moderate
172.1Moderate
182.2Moderate
192.2Moderate
202.2Moderate
212.3Moderate
222.3Moderate
232.3Moderate
242.4Moderate
252.4Moderate
262.4Moderate
272.5Moderate
282.5Moderate
292.5Moderate
302.6Moderate
312.6Moderate
Planning a trip in January

Hazard calendar for Trenton

In seasonPeak

None of Trenton's seasonal hazards are active in January. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Trenton 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 January a good time to visit Trenton?

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 Trenton.

What to pack for Trenton in January

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

In January, Trenton sees daytime highs around 40°F and nights near 27°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 9 days see rain.

a warm layera heavy coatrain gear

UV index in Trenton 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 Trenton peaks around July 11 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 8Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Trenton 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 Trenton is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1518 µg/m³Nov 149 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar14Moderate
Apr14Moderate
May16Moderate
Jun17Moderate
Jul18Moderate
Aug15Moderate
Sep13Moderate
Oct10Good
Nov9Good
Dec10Good
Location & terrain

Where is Trenton?

Trenton sits at 40.2°N, 74.7°W, 56 ft above sea level, in United States. The nearest listed city is Mercerville-Hamilton Square, 3.7 mi away.

Topography around Trenton

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

Within 2 miles, the terrain around Trenton has only modest variations in elevation — a maximum elevation change of 135 ft around an average of 59 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 515 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,535 ft.

The land around Trenton is covered by artificial surfaces (53%) and trees (32%) within 2 miles, trees (56%) within 10 miles, and trees (62%) within 50 miles.

2 miles
135 ft
10 miles
515 ft
50 miles
1,535 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
January weather nearby: Mercerville-Hamilton Square 3.7 mi · Ewing 5.0 mi · Levittown 6.2 mi · Princeton 9.9 mi · Bensalem 14 mi · Parkwood Manor 15 mi · Willingboro 15 mi · Somerton 16 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 Trenton (40.2171°, -74.7429°, elevation 56 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).