January is one of the cooler months of the year in Allentown, with average highs near 1.4°C and lows around -7°C (mean -2.8°C). It is one of the drier months, averaging 81 mm of rainfall and 87% relative humidity across the period.
January is one of the cooler months of the year in Allentown. Across 45 years of records, the warmest January in Allentown was 2023 — when the month averaged 2.5°C — while the coldest was 1994 at -8.9°C. Typical January days reach 1.4°C with nights near -7°C. The long-term trend is warming, about 0.7°C per decade.
January is one of the drier months in Allentown, averaging 81 mm of rainfall. The wettest January on record was 1996 with 192 mm, while the driest was 1981 at 16 mm.
Relative humidity in Allentown during January averages 87%. The most humid January was 1994 at 96%, and the least humid was 2025 at 79%.
January receives about 1.8 kWh/m²/day of solar energy in Allentown. The sunniest Januarys were 2008, 2016 and 2025, among others at 2.1 kWh/m²/day, and the cloudiest were 2017, 2023 and 2024 at 1.5.
Average wind speed in Allentown during January is 0.9 m/s. The windiest Januarys were 1997, 2000 and 2004 at 1.1 m/s, while the calmest were 2011, 2013 and 2023, among others at 0.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -4.8°C | -2.3°C | -2.6°C | -2.9°C | -1.0°C | +3.8°C |
| Avg High | -0.4°C | 2.0°C | 1.6°C | 1.2°C | 3.0°C | +3.4°C |
| Avg Low | -9.1°C | -6.5°C | -6.7°C | -7.0°C | -5.1°C | +4°C |
| Avg Rain | 63 mm | 108 mm | 72 mm | 80 mm | 78 mm | +15 mm |
January temperatures in Allentown have risen by about 4.3°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -27.5°C (1994) to a record high of 18.6°C (1998).
Rainfall in January is one of the drier months, averaging 81 mm, with a wettest year of 192 mm.
A quieter season to visit Allentown
If your dates are flexible, the more temperate months of August and June tend to be the most comfortable for visiting Allentown. That said, January — with days averaging 1.4°C and nights around -7°C (mean -2.8°C) and higher rainfall (81 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 0.5°C | -3.7°C | -7.8°C | 7.3°C | -16.9°C | 22 mm | 79% | 1 m/s | 2.1 |
| 2024 | 3.4°C | -0.6°C | -4.6°C | 17.2°C | -13.2°C | 161 mm | 89% | 0.9 m/s | 1.5 |
| 2023 🔥 | 6.4°C | 2.5°C | -1.5°C | 13.4°C | -5.9°C | 99 mm | 89% | 0.8 m/s | 1.5 |
| 2022 | 0.6°C | -4.0°C | -8.5°C | 12.3°C | -17.4°C | 71 mm | 82% | 1 m/s | 2 |
| 2021 | 2.2°C | -1.2°C | -4.6°C | 8.1°C | -9.6°C | 50 mm | 87% | 0.9 m/s | 1.9 |
| 2020 | 5.0°C | 0.7°C | -3.5°C | 17.0°C | -11.8°C | 66 mm | 84% | 0.9 m/s | 1.9 |
| 2019 | 1.2°C | -3.1°C | -7.4°C | 12.0°C | -19.9°C | 110 mm | 87% | 1 m/s | 1.8 |
| 2018 | 1.6°C | -3.1°C | -7.9°C | 16.4°C | -19.6°C | 73 mm | 83% | 1 m/s | 1.9 |
| 2017 | 3.6°C | 0.3°C | -3.0°C | 12.8°C | -12.3°C | 83 mm | 85% | 0.9 m/s | 1.5 |
| 2016 | 1.6°C | -2.7°C | -7.0°C | 15.0°C | -14.3°C | 79 mm | 84% | 0.9 m/s | 2.1 |
| 2015 | -0.9°C | -5.1°C | -9.3°C | 7.1°C | -15.5°C | 90 mm | 85% | 0.9 m/s | 1.8 |
| 2014 | -1.0°C | -5.6°C | -10.2°C | 11.3°C | -19.3°C | 81 mm | 85% | 1 m/s | 1.9 |
| 2013 | 2.4°C | -1.4°C | -5.3°C | 16.2°C | -13.0°C | 86 mm | 88% | 0.8 m/s | 1.8 |
| 2012 | 3.6°C | -0.4°C | -4.4°C | 13.8°C | -13.2°C | 73 mm | 88% | 0.9 m/s | 2 |
| 2011 | -1.0°C | -5.1°C | -9.2°C | 7.5°C | -18.3°C | 59 mm | 90% | 0.8 m/s | 1.7 |
| 2010 | 1.2°C | -2.8°C | -6.8°C | 13.8°C | -14.4°C | 64 mm | 86% | 1 m/s | 1.9 |
| 2009 | -1.5°C | -5.6°C | -9.8°C | 5.4°C | -20.0°C | 60 mm | 88% | 0.9 m/s | 1.9 |
| 2008 | 3.2°C | -1.0°C | -5.1°C | 14.8°C | -13.5°C | 38 mm | 86% | 0.8 m/s | 2.1 |
| 2007 | 4.7°C | 0.7°C | -3.4°C | 18.2°C | -13.5°C | 80 mm | 86% | 0.9 m/s | 1.7 |
| 2006 | 5.9°C | 1.4°C | -3.1°C | 14.0°C | -9.6°C | 130 mm | 89% | 0.9 m/s | 1.8 |
| 2005 | 0.0°C | -4.1°C | -8.3°C | 16.0°C | -21.4°C | 125 mm | 92% | 0.9 m/s | 1.6 |
| 2004 | -2.4°C | -6.3°C | -10.1°C | 11.5°C | -18.0°C | 52 mm | 85% | 1.1 m/s | 2 |
| 2003 | -1.7°C | -5.4°C | -9.1°C | 6.8°C | -16.3°C | 48 mm | 86% | 1 m/s | 1.8 |
| 2002 | 5.1°C | 0.7°C | -3.7°C | 18.2°C | -11.4°C | 53 mm | 85% | 0.8 m/s | 1.9 |
| 2001 | 1.6°C | -2.8°C | -7.2°C | 6.4°C | -15.5°C | 58 mm | 91% | 0.8 m/s | 1.9 |
| 2000 | 0.8°C | -3.4°C | -7.6°C | 15.4°C | -17.0°C | 73 mm | 84% | 1.1 m/s | 2 |
| 1999 | 2.7°C | -2.1°C | -6.9°C | 16.3°C | -16.3°C | 162 mm | 86% | 0.9 m/s | 1.8 |
| 1998 | 5.4°C | 1.4°C | -2.7°C | 18.6°C | -14.2°C | 116 mm | 90% | 0.9 m/s | 1.6 |
| 1997 | 0.7°C | -3.4°C | -7.4°C | 13.2°C | -20.2°C | 75 mm | 87% | 1.1 m/s | 1.8 |
| 1996 🌧️ | -0.9°C | -5.5°C | -10.0°C | 11.7°C | -23.4°C | 192 mm | 94% | 1 m/s | 1.6 |
| 1995 | 3.3°C | -0.4°C | -4.1°C | 15.9°C | -12.9°C | 95 mm | 88% | 0.9 m/s | 2 |
| 1994 ❄️ | -3.9°C | -8.9°C | -13.9°C | 6.3°C | -27.5°C | 140 mm | 96% | 0.9 m/s | 1.8 |
| 1993 | 3.0°C | -0.7°C | -4.4°C | 13.8°C | -9.9°C | 59 mm | 86% | 0.9 m/s | 1.8 |
| 1992 | 2.9°C | -1.4°C | -5.6°C | 15.4°C | -13.4°C | 55 mm | 84% | 1 m/s | 1.8 |
| 1991 | 1.7°C | -2.5°C | -6.8°C | 8.9°C | -13.0°C | 73 mm | 87% | 0.9 m/s | 2 |
| 1990 | 4.8°C | 0.7°C | -3.4°C | 14.1°C | -9.2°C | 118 mm | 89% | 0.8 m/s | 1.7 |
| 1989 | 3.3°C | -1.1°C | -5.5°C | 10.7°C | -15.0°C | 51 mm | 85% | 0.9 m/s | 1.8 |
| 1988 | -0.8°C | -4.9°C | -9.0°C | 8.2°C | -16.2°C | 64 mm | 87% | 0.8 m/s | 1.9 |
| 1987 | -0.8°C | -5.0°C | -9.1°C | 9.5°C | -25.1°C | 94 mm | 95% | 0.9 m/s | 1.7 |
| 1986 | 1.3°C | -3.4°C | -8.1°C | 11.4°C | -21.4°C | 98 mm | 88% | 0.9 m/s | 2 |
| 1985 | -1.2°C | -5.2°C | -9.1°C | 13.6°C | -21.9°C | 28 mm | 83% | 1 m/s | 2.1 |
| 1984 | -2.4°C | -7.2°C | -12.0°C | 6.2°C | -26.2°C | 42 mm | 94% | 0.8 m/s | 1.7 |
| 1983 | 1.6°C | -2.4°C | -6.5°C | 7.7°C | -16.3°C | 75 mm | 87% | 0.8 m/s | — |
| 1982 | -3.0°C | -7.4°C | -11.8°C | 11.8°C | -22.3°C | 100 mm | 88% | 1 m/s | — |
| 1981 | -1.9°C | -6.5°C | -11.0°C | 6.7°C | -20.1°C | 16 mm | 85% | 0.9 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 1.4°C with lows near -7°C (mean -2.8°C), based on 45 years of NASA POWER data.
January averages 81 mm of rainfall in Allentown, one of the drier months. The wettest on record was 192 mm in 1996.
The hottest January reached 18.6°C in 1998. The coldest dipped to -27.5°C in 1994.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 4.3°C. Daytime highs moved from -1.4°C to 2.6°C and overnight lows from -10.1°C to -5.4°C over the same span.
January is one of the cooler months of the year in Allentown and one of the drier months, so plan for around 1.4°C daytime highs and -7°C at night.
Yes — January is the coldest month of the year in Allentown, averaging -2.8°C.
For January in Allentown, pack warm layers and a jacket for chilly mornings, with typical highs of 1.4°C and lows of -7°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 87% — quite humid.
Average wind speed in January is 0.9 m/s. The windiest January on record averaged 1.1 m/s (1997).
The wettest January on record was 1996 with 192 mm. On average, January sees 81 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Allentown behaves each January, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for January specifically, along with year-by-year records and how the month has changed over the decades.
