Allentown weather in January

In January, Allentown sees average daytime highs of 38°F and overnight lows near 24°F, with 3.4 in of precipitation across 9.5 wet days and about 9.4 hours of daylight. It is the 12th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 38°F through the month. The sky is clear or mostly clear about 26% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 06 min at the start of January to 9 h 48 min by month's end. Set against the rest of the year, January is Allentown's 9th-clearest and 2nd-windiest month. For the whole year in context, see Allentown's year-round climate.

Daytime high
38°
12th warmest
Overnight low
24°
1st coldest
Precipitation
3.4 in
9.5 wet days
Daylight
9 h 24 min
7:29 AM – 4:53 PM
Cloud cover
64%
9th clearest
Wind
7 mph
2nd windiest
Solar energy
2.09 kWh/m²
Travel score
0.0
out of 10

Allentown is city in and seat of Lehigh County, Pennsylvania, United States.

Density
2,575/km²
people per km²
Founded
1762

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 38°F through the month.

A typical January day in Allentown reaches about 38°F in the afternoon and slips back to 24°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 24°F and 51°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)
14026
23926
33926
43926
53926
63926
73926
83825
93825
103825
113825
123825
133824
143824
153724
163724
173724
183723
193723
203723
213723
223723
233723
243723
253722
263722
273723
283723
293823
303823
313823

How January really feels in Allentown

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
5 feel bitter (≤ 14°F)

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

Allentown 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
Jan38° / 24°3.49.54.89.40.0
Feb41° / 25°3.08.9410.40.2
Mar49° / 32°4.0113.511.72.1
Apr62° / 43°3.910.60.4135.0
May71° / 52°3.711.5014.26.3
Jun81° / 62°4.111.4014.86.0
Jul85° / 67°3.811.2014.65.0
Aug83° / 65°3.710.1013.65.8
Sep76° / 58°4.48.8012.37.0
Oct64° / 46°3.98.90.110.95.8
Nov52° / 36°3.28.10.69.73.0
Dec42° / 29°4.09.42.99.10.4

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 15% of January, with mostly cloudy or overcast conditions the remaining 59%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14555
24456
34357
44357
54357
64258
74060
84060
94060
104060
114060
124060
133961
144060
154060
164060
174060
183961
193961
203961
214060
224159
234159
244159
254159
264357
274357
284357
294357
304456
314456

Chance of precipitation in January

Any precipitationSnow

Allentown gets around 3.4 in of rain and snow over 9.5 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 31% and peaks near 33% on the wettest days, and about 5 days bring snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
13012
23013
33013
43114
53114
63215
73215
83315
93316
103316
113316
123316
133316
143316
153316
163216
173216
183216
193116
203116
213016
223016
232916
242915
252815
262815
272815
282815
292815
302815
312815

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 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
11000
21000
31000
41000
51000
61000
71000
8991
9991
10991
11991
12991
13991
14991
15991
161000
171000
181000
191000
201000
211000
221000
231000
241000
251000
261000
271000
281000
291000
301000
311000

Wind in January

Winds average 7 mph in January.

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

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 06 min at the start of January to 9 h 48 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 7:31 AM to 7:20 AM, and sunset from 4:39 PM to 5:10 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.17:314:39
29.27:314:40
39.27:314:41
49.27:314:42
59.27:314:43
69.27:314:43
79.27:314:44
89.27:314:45
99.37:314:46
109.37:314:47
119.37:314:48
129.37:314:49
139.37:304:50
149.47:304:51
159.47:304:52
169.47:294:53
179.47:294:54
189.47:294:55
199.57:284:56
209.57:284:57
219.57:274:59
229.67:275:00
239.67:265:01
249.67:255:02
259.67:255:03
269.77:245:04
279.77:235:05
289.77:235:07
299.87:225:08
309.87:215:09
319.87:205:10

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.09 kWh/m².

For context, solar energy here swings from a low near 1.76 kWh/m² to a high of 6.02 kWh/m² in June across the year — January's 2.09 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.8Dim
21.8Dim
31.8Dim
41.8Dim
51.9Dim
61.9Dim
71.9Dim
81.9Dim
91.9Dim
101.9Dim
111.9Dim
122.0Dim
132.0Dim
142.0Moderate
152.0Moderate
162.1Moderate
172.1Moderate
182.1Moderate
192.1Moderate
202.2Moderate
212.2Moderate
222.3Moderate
232.3Moderate
242.3Moderate
252.4Moderate
262.4Moderate
272.4Moderate
282.5Moderate
292.5Moderate
302.5Moderate
312.6Moderate
Planning a trip in January

Is January a good time to visit Allentown?

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 Allentown.

What to pack for Allentown in January

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

In January, Allentown sees daytime highs around 38°F and nights near 24°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 10 days see rain.

a warm layera heavy coatrain gear

UV index in Allentown 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 Allentown peaks around July 10 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 10UV 8Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Allentown 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 Allentown is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1417 µg/m³Nov 148 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb12Good
Mar13Moderate
Apr13Moderate
May16Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Good
Oct9Good
Nov8Good
Dec9Good
Location & terrain

Where is Allentown?

Allentown sits at 40.6°N, 75.5°W, 338 ft above sea level, in United States. The nearest listed city is Whitehall Township, 4.3 mi away.

Topography around Allentown

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

Within 2 miles, the terrain around Allentown has only modest variations in elevation — a maximum elevation change of 285 ft around an average of 344 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,125 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,516 ft.

The land around Allentown is covered by trees (43%) and artificial surfaces (42%) within 2 miles, trees (47%) and grassland (22%) within 10 miles, and trees (71%) within 50 miles.

2 miles
285 ft
10 miles
1,125 ft
50 miles
2,516 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: Whitehall Township 4.3 mi · Bethlehem 6.2 mi · Easton 15 mi · Limerick 26 mi · Pottstown 27 mi · Lansdale 27 mi · Reading 30 mi · Phoenixville 33 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 Allentown (40.6084°, -75.4902°, elevation 338 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).