Climateby Month

Allentown, PA climate by month

NOAA 1991-2020 normals · 342 ft elevation

Allentown has warm and often humid summers and cold and snowy winters. Highs peak at 86°F in July and fall to 38°F in January. Wet days are spread through the year, from about 9 to 12 a month. Normal snowfall is about 33 in a year. By our comfort score the best month is May.

Warmest month
86°F
July normal high
Coldest month
22°F
January normal low
Wet days a year
129
47.4 in of precipitation
Snow a year
33.1 in
normal snowfall

How warm is Allentown?

Normal highs range from 38°F in January to 86°F in July.

20°40°60°80°100° January: normal high 38°F (3°C), low 22°F (-6°C) 38° 22° February: normal high 42°F (6°C), low 23°F (-5°C) March: normal high 51°F (11°C), low 31°F (-1°C) April: normal high 63°F (17°C), low 40°F (4°C) May: normal high 74°F (23°C), low 51°F (11°C) June: normal high 82°F (28°C), low 60°F (16°C) July: normal high 86°F (30°C), low 65°F (18°C) 86° 65° August: normal high 84°F (29°C), low 63°F (17°C) September: normal high 77°F (25°C), low 55°F (13°C) October: normal high 66°F (19°C), low 44°F (7°C) November: normal high 54°F (12°C), low 34°F (1°C) December: normal high 43°F (6°C), low 27°F (-3°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Allentown?

May has the most wet days (about 12); the year brings about 47 in of precipitation.

January: 11 wet days February: 10 wet days March: 11 wet days April: 12 wet days May: 12 wet days 12 June: 11 wet days July: 11 wet days August: 10 wet days September: 10 wet days October: 10 wet days November: 9 wet days 9 December: 12 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 33.1 in a year, most of it in February.

January: 9.8 in of snow February: 10.8 in of snow 10.8 March: 6.3 in of snow April: 0.5 in of snow May: 0.0 in of snow 0.0 June: 0.0 in of snow July: 0.0 in of snow August: 0.0 in of snow September: 0.0 in of snow October: 0.2 in of snow November: 0.9 in of snow December: 4.6 in of snow JFMAMJJASOND

How humid is Allentown?

Muggy days peak in July, at about 14 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 1 muggy days June: 7 muggy days July: 14 muggy days 14 August: 12 muggy days September: 5 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Lehigh Valley International Airport, 3.6 mi NE of the city center.

How much daylight?

Daylight ranges from about 9.3 hours in December to 15.0 hours in June.

January: 9.7 hours of daylight February: 10.7 hours of daylight March: 12.0 hours of daylight April: 13.3 hours of daylight May: 14.4 hours of daylight June: 15.0 hours of daylight 15.0 July: 14.7 hours of daylight August: 13.7 hours of daylight September: 12.5 hours of daylight October: 11.1 hours of daylight November: 9.9 hours of daylight December: 9.3 hours of daylight 9.3 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Allentown, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 38°F22°F 3.3 in11 9.8 in 0 9.7 h
February 42°F23°F 2.8 in10 10.8 in 0 10.7 h
March 51°F31°F 3.6 in11 6.3 in 0 12.0 h
April 63°F40°F 3.7 in12 0.5 in 0 13.3 h
May 74°F51°F 3.6 in12 0.0 in 1 14.4 h
June 82°F60°F 4.4 in11 0.0 in 7 15.0 h
July 86°F65°F 5.3 in11 0.0 in 14 14.7 h
August 84°F63°F 4.6 in10 0.0 in 12 13.7 h
September 77°F55°F 4.8 in10 0.0 in 5 12.5 h
October 66°F44°F 4.1 in10 0.2 in 0 11.1 h
November 54°F34°F 3.2 in9 0.9 in 0 9.9 h
December 43°F27°F 3.9 in12 4.6 in 0 9.3 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Allentown

By our comfort score, the best month is May.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 290620
Feb 351615
Mar 47376
Apr 641171
May 721681
Jun 64973
Jul 52388
Aug 54575
Sep 661472
Oct 621360
Nov 46463
Dec 321714

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Allentown

The last spring frost typically comes around Apr 20, and the first fall frost around Oct 24, leaving 184 frost-free days in a typical year.

Frost and freeze dates for Allentown
Typical date1 year in 10
Last spring frost (32°F)Apr 20after May 6
First fall frost (32°F)Oct 24before Oct 8
Last hard freeze (28°F)Apr 5after Apr 18
First hard freeze (28°F)Nov 4before Oct 19
Frost-free season184 daysunder 163 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Allentown Intl Airport (USW00014737), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Pennsylvania.

Hottest and coldest readings, 1991-2020

The highest reading was 104°F (July 22, 2011); the lowest was -15°F (January 21, 1994).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Allentown

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Allentown Intl Airport (USW00014737), 3.6 mi NE of the city center, 390 ft . NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Lehigh Valley International Airport (725170-14737), 3.6 mi NE of the city center, 385 ft . Hourly observations, 1991-2020.

Distances from the city center (USGS). Methodology · Report an error