Allentown climate
Allentown (Pennsylvania, United States) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 11 °C52 °F, and about 1,233 mm49 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Allentown climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | 236 | −621 | −228 | 753.0 | 28 |
| Feb | 438 | −622 | −130 | 742.9 | 26 |
| Mar | 948 | −229 | 438 | 913.6 | 22 |
| Apr | 1661 | 439 | 1050 | 973.8 | 6 |
| May | 2272 | 1051 | 1661 | 1034.1 | 0 |
| Jun | 2781 | 1660 | 2170 | 1244.9 | 0 |
| Jul | 3086 | 1966 | 2476 | 1265.0 | 0 |
| Aug | 2985 | 1864 | 2374 | 1184.7 | 0 |
| Sep | 2678 | 1457 | 2067 | 1194.7 | 0 |
| Oct | 1865 | 745 | 1355 | 1164.5 | 2 |
| Nov | 1152 | 134 | 643 | 863.4 | 14 |
| Dec | 541 | −326 | 133 | 1044.1 | 25 |
| Year | 3086 | −621 | 1152 | 1,23349 | 123 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 87% | 66% | 1.9 | 9:34 |
| Feb | 86% | 64% | 2.7 | 10:36 |
| Mar | 82% | 63% | 3.6 | 11:49 |
| Apr | 78% | 62% | 4.8 | 13:14 |
| May | 79% | 64% | 5.3 | 14:25 |
| Jun | 77% | 59% | 5.9 | 15:04 |
| Jul | 72% | 54% | 6.0 | 14:48 |
| Aug | 72% | 54% | 5.2 | 13:46 |
| Sep | 73% | 52% | 4.2 | 12:24 |
| Oct | 79% | 58% | 2.9 | 11:02 |
| Nov | 82% | 60% | 2.1 | 9:51 |
| Dec | 87% | 68% | 1.6 | 9:17 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Allentown is like
The warmest month is July, with an average high of 30 °C86 °F and a low of 19 °C66 °F. The coldest is January, when highs average 2 °C36 °F and lows −6 °C21 °F. Seasons are strongly marked: the warmest month is on average 26.5 °C47.7 °F warmer than the coldest.
It is wet, with about 1,233 mm49 in of precipitation per year. Rain is spread fairly evenly through the year. The wettest month is July (126 mm5.0 in), the driest is February (74 mm2.9 in).
Relative humidity ranges from 72% in July to 87% in December. The clearest skies (lowest average cloud amount, 52%) are typical of September. Average wind speed near the ground ranges from 1 km/h (1 mph) in July to 4 km/h (2 mph) in February. Daylight lasts from about 9.3 hours in December to 15.1 hours in June.
A lasting snow cover is typical in December–February, when the average snow depth in the reanalysis exceeds 10 cm (deepest in February, about 15 cm).
Best time to visit Allentown
Based on these averages, the most comfortable months for sightseeing and outdoor activities are May and September: average highs of 22 °C72 °F to 26 °C78 °F with 103 mm4.1 in to 119 mm4.7 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of 2 °C36 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Allentown
- Winter (December–February) — highs 236 to 5 °C41 °F, lows −621 to −3 °C26 °F, about 84 mm3.3 in of precipitation a month. Pack a winter coat, hat, gloves and warm, non-slip boots and shoes with good grip, as frost is common.
- Spring (March–May) — highs 948 to 22 °C72 °F, lows −229 to 10 °C51 °F, about 97 mm3.8 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Summer (June–August) — highs 2781 to 30 °C86 °F, lows 1660 to 19 °C66 °F, about 123 mm4.8 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Autumn (September–November) — highs 1152 to 26 °C78 °F, lows 134 to 14 °C57 °F, about 107 mm4.2 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
How Allentown compares
Compared with Philadelphia, about 78 km to the south, Allentown is on average 1 °C1.7 °F cooler and receives a similar amount of precipitation. The difference is largest in February (1.5 °C2.7 °F cooler).
Of the 222 places in the United States covered by World Climates, Allentown is the 173rd warmest by annual mean temperature and the 53rd wettest by annual precipitation. See all of them on the United States climate page.
Places in other countries with the most similar temperature and rainfall pattern: Ichinoseki (Japan, Dfa), Oshu (Japan, Dfa) and Fukushima (Japan, Dfa).
Nearby places
- Philadelphia 78 km · 12 °C54 °F · 1,226 mm48 in
- Wilkes-Barre 78 km · 11 °C51 °F · 1,214 mm48 in
- Staten Island 114 km · 12 °C53 °F · 1,226 mm48 in
- Paterson 116 km · 11 °C52 °F · 1,240 mm49 in
- New York City 126 km · 12 °C54 °F · 1,312 mm52 in
- Manhattan 130 km · 11 °C52 °F · 1,236 mm49 in
- Brooklyn 130 km · 12 °C54 °F · 1,312 mm52 in
- Atlantic City 166 km · 13 °C55 °F · 1,203 mm47 in
Frequently asked questions
What is the warmest month in Allentown?
July is the warmest month in Allentown, with an average high of 30 °C (86 °F) and an average low of 19 °C (66 °F).
What is the coldest month in Allentown?
January is the coldest month, with an average high of 2 °C (36 °F) and an average low of -6 °C (21 °F).
When does it rain the most in Allentown?
July is the wettest month with about 126 mm (5.0 in) of precipitation; February is the driest with about 74 mm (2.9 in).
What is the best time to visit Allentown?
Judging by long-term averages, the most comfortable months are May and September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 179 m, while Allentown lies at about 103 m. Temperatures on this page were therefore adjusted by +0.5 °C0.9 °F using the standard lapse rate of 6.5 °C per 1,000 m.