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Allentown, Pennsylvania climate
Cfa Humid subtropical
Allentown has a strongly seasonal cool-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 30°C, while the coldest is January averaging around −6°C at night. Precipitation is fairly even year-round, totalling about 1203 mm. Winters bring significant snowfall (84 cm of snow per year on average).
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation split into rain and snow · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsAllentown climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 4 | 5 | 10 | 17 | 23 | 28 | 30 | 29 | 25 | 19 | 12 | 6 |
| Avg temp (°C) | −1 | 0 | 5 | 11 | 17 | 22 | 24 | 23 | 19 | 13 | 7 | 2 |
| Avg low (°C) | −6 | −5 | −1 | 5 | 10 | 16 | 18 | 17 | 13 | 7 | 1 | −3 |
| Precipitation (mm) | 84 | 70 | 92 | 93 | 93 | 112 | 135 | 116 | 123 | 105 | 82 | 98 |
| Snowfall (cm) | 25 | 27 | 16 | 1 | — | — | — | — | — | 1 | 2 | 12 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 4 | 5 | 10 | 17 | 23 | 28 |
| Avg temp (°C) | −1 | 0 | 5 | 11 | 17 | 22 |
| Avg low (°C) | −6 | −5 | −1 | 5 | 10 | 16 |
| Precipitation (mm) | 84 | 70 | 92 | 93 | 93 | 112 |
| Snowfall (cm) | 25 | 27 | 16 | 1 | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 30 | 29 | 25 | 19 | 12 | 6 |
| Avg temp (°C) | 24 | 23 | 19 | 13 | 7 | 2 |
| Avg low (°C) | 18 | 17 | 13 | 7 | 1 | −3 |
| Precipitation (mm) | 135 | 116 | 123 | 105 | 82 | 98 |
| Snowfall (cm) | — | — | — | 1 | 2 | 12 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 11 | 10 | 11 | 12 | 12 | 11 | 11 | 10 | 10 | 10 | 9 | 12 |
| Days with high ≥ 32°C (days) | — | — | — | 0.2 | 1 | 3 | 8 | 5 | 2 | 0.1 | — | — |
| Days with low ≤ 0°C (days) | 27 | 24 | 19 | 6 | 0.4 | — | — | — | 0.0 | 3 | 15 | 24 |
| Days with snowfall ≥ 2.5 cm (days) | 2 | 2 | 1 | 0.1 | — | — | — | — | — | 0.0 | 0.3 | 1 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 11 | 10 | 11 | 12 | 12 | 11 |
| Days with high ≥ 32°C (days) | — | — | — | 0.2 | 1 | 3 |
| Days with low ≤ 0°C (days) | 27 | 24 | 19 | 6 | 0.4 | — |
| Days with snowfall ≥ 2.5 cm (days) | 2 | 2 | 1 | 0.1 | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 11 | 10 | 10 | 10 | 9 | 12 |
| Days with high ≥ 32°C (days) | 8 | 5 | 2 | 0.1 | — | — |
| Days with low ≤ 0°C (days) | — | — | 0.0 | 3 | 15 | 24 |
| Days with snowfall ≥ 2.5 cm (days) | — | — | — | 0.0 | 0.3 | 1 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 66 | 64 | 65 | 65 | 65 | 62 | 57 | 56 | 56 | 58 | 63 | 67 |
| Clear days (≤ 30% cloud) | 4 | 4 | 5 | 6 | 4 | 5 | 7 | 8 | 8 | 8 | 5 | 4 |
| Partly cloudy days (30–70%) | 11 | 10 | 10 | 9 | 11 | 11 | 13 | 12 | 10 | 11 | 10 | 11 |
| Cloudy days (≥ 70%) | 16 | 14 | 15 | 16 | 15 | 13 | 12 | 12 | 12 | 13 | 14 | 16 |
| Relative humidity (%) | 87 | 86 | 82 | 79 | 78 | 77 | 71 | 71 | 73 | 78 | 82 | 87 |
| Wind speed (km/h) | 3.3 | 3.8 | 3.4 | 2.3 | 1.6 | 1.4 | 1.4 | 1.4 | 1.5 | 1.6 | 1.6 | 2.2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 66 | 64 | 65 | 65 | 65 | 62 |
| Clear days (≤ 30% cloud) | 4 | 4 | 5 | 6 | 4 | 5 |
| Partly cloudy days (30–70%) | 11 | 10 | 10 | 9 | 11 | 11 |
| Cloudy days (≥ 70%) | 16 | 14 | 15 | 16 | 15 | 13 |
| Relative humidity (%) | 87 | 86 | 82 | 79 | 78 | 77 |
| Wind speed (km/h) | 3.3 | 3.8 | 3.4 | 2.3 | 1.6 | 1.4 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 57 | 56 | 56 | 58 | 63 | 67 |
| Clear days (≤ 30% cloud) | 7 | 8 | 8 | 8 | 5 | 4 |
| Partly cloudy days (30–70%) | 13 | 12 | 10 | 11 | 10 | 11 |
| Cloudy days (≥ 70%) | 12 | 12 | 12 | 13 | 14 | 16 |
| Relative humidity (%) | 71 | 71 | 73 | 78 | 82 | 87 |
| Wind speed (km/h) | 1.4 | 1.4 | 1.5 | 1.6 | 1.6 | 2.2 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Allentown Lehigh Vly Intl AP (NOAA GHCN station USW00014737), about 6 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.