April is one of the cooler months of the year in Allentown, with average highs near 15.4°C and lows around 3.2°C (mean 9.3°C). It is about average for rainfall, averaging 98 mm of rainfall and 79% relative humidity across the period.
April is one of the cooler months of the year in Allentown. Across 45 years of records, the warmest April in Allentown was 2017 — when the month averaged 12.6°C — while the coldest was 1982 at 6.6°C. Typical April days reach 15.4°C with nights near 3.2°C. The long-term trend is warming, about 0.4°C per decade.
April is about average for rainfall in Allentown, averaging 98 mm of rainfall. The wettest April on record was 1983 with 242 mm, while the driest was 1985 at 22 mm.
Relative humidity in Allentown during April averages 79%. The most humid April was 1984 at 85%, and the least humid was 2012 at 73%.
April receives about 4.7 kWh/m²/day of solar energy in Allentown. The sunniest April was 2010 at 5.5 kWh/m²/day, and the cloudiest was 2011 at 3.8.
Average wind speed in Allentown during April is 0.6 m/s. The windiest April was 1982 at 0.8 m/s, while the calmest were 2021, 2023 and 2024, among others at 0.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 8.4°C | 8.9°C | 9.7°C | 9.9°C | 10.0°C | +1.6°C |
| Avg High | 14.5°C | 14.9°C | 15.8°C | 16.0°C | 16.0°C | +1.5°C |
| Avg Low | 2.4°C | 2.8°C | 3.6°C | 3.6°C | 3.9°C | +1.5°C |
| Avg Rain | 105 mm | 94 mm | 97 mm | 93 mm | 106 mm | +2 mm |
April temperatures in Allentown have risen by about 1.8°C between 1981–1985 and 2021–2025.
April has ranged from a record low of -9.4°C (1982) to a record high of 32.1°C (2002).
Rainfall in April is about average for rainfall, averaging 98 mm, with a wettest year of 242 mm.
A good time to visit Allentown
April is a good time to visit Allentown, with days averaging 15.4°C and nights around 3.2°C (mean 9.3°C, cooler than Allentown's yearly average) and higher rainfall. August and June are marginally more temperate, but April still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 16.9°C | 10.6°C | 4.3°C | 25.5°C | -5.2°C | 69 mm | 74% | 0.7 m/s | 4.6 |
| 2024 | 16.6°C | 10.8°C | 4.9°C | 29.4°C | -1.0°C | 121 mm | 81% | 0.6 m/s | 4.5 |
| 2023 | 18.4°C | 12.0°C | 5.6°C | 28.9°C | -3.5°C | 138 mm | 77% | 0.6 m/s | 4.9 |
| 2022 | 14.7°C | 8.6°C | 2.6°C | 24.8°C | -2.6°C | 135 mm | 77% | 0.7 m/s | 4.9 |
| 2021 | 16.2°C | 10.0°C | 3.8°C | 26.9°C | -5.1°C | 47 mm | 78% | 0.6 m/s | 4.9 |
| 2020 | 13.3°C | 7.8°C | 2.3°C | 21.9°C | -3.3°C | 128 mm | 78% | 0.7 m/s | 4.3 |
| 2019 | 17.2°C | 11.2°C | 5.1°C | 23.7°C | -4.0°C | 112 mm | 80% | 0.7 m/s | 4.6 |
| 2018 | 13.0°C | 7.2°C | 1.4°C | 26.6°C | -3.8°C | 99 mm | 78% | 0.7 m/s | 4.4 |
| 2017 🔥 | 18.8°C | 12.6°C | 6.4°C | 27.8°C | -2.6°C | 78 mm | 80% | 0.6 m/s | 4.5 |
| 2016 | 15.2°C | 9.0°C | 2.8°C | 25.2°C | -5.6°C | 55 mm | 75% | 0.6 m/s | 5 |
| 2015 | 15.7°C | 9.2°C | 2.7°C | 23.7°C | -4.7°C | 62 mm | 78% | 0.6 m/s | 4.9 |
| 2014 | 14.8°C | 8.2°C | 1.5°C | 23.3°C | -6.0°C | 165 mm | 79% | 0.6 m/s | 5 |
| 2013 | 15.9°C | 9.7°C | 3.5°C | 24.4°C | -4.7°C | 70 mm | 77% | 0.6 m/s | 5.3 |
| 2012 | 15.8°C | 9.4°C | 2.9°C | 28.3°C | -2.2°C | 60 mm | 73% | 0.6 m/s | 5.4 |
| 2011 | 15.9°C | 10.5°C | 5.1°C | 25.6°C | -1.9°C | 165 mm | 84% | 0.7 m/s | 3.8 |
| 2010 | 18.1°C | 11.5°C | 4.9°C | 27.2°C | -0.5°C | 68 mm | 77% | 0.6 m/s | 5.5 |
| 2009 | 16.2°C | 10.0°C | 3.9°C | 30.9°C | -4.3°C | 85 mm | 77% | 0.7 m/s | 4.7 |
| 2008 | 17.0°C | 10.9°C | 4.7°C | 26.6°C | -4.4°C | 71 mm | 79% | 0.6 m/s | 4.9 |
| 2007 | 12.9°C | 7.5°C | 2.2°C | 25.5°C | -3.8°C | 165 mm | 80% | 0.7 m/s | 4.3 |
| 2006 | 17.2°C | 10.6°C | 4.0°C | 25.2°C | -3.1°C | 100 mm | 76% | 0.6 m/s | 5.4 |
| 2005 | 16.9°C | 10.4°C | 3.9°C | 25.5°C | -1.9°C | 139 mm | 79% | 0.6 m/s | 5.2 |
| 2004 | 15.7°C | 9.8°C | 3.9°C | 26.8°C | -3.7°C | 116 mm | 80% | 0.6 m/s | 4.6 |
| 2003 | 14.1°C | 8.3°C | 2.5°C | 25.4°C | -5.5°C | 64 mm | 82% | 0.6 m/s | 4.3 |
| 2002 | 17.6°C | 11.1°C | 4.6°C | 32.1°C | -5.4°C | 92 mm | 75% | 0.6 m/s | 4.7 |
| 2001 | 16.3°C | 9.7°C | 3.1°C | 28.1°C | -4.2°C | 56 mm | 78% | 0.6 m/s | 4.8 |
| 2000 | 14.5°C | 8.6°C | 2.7°C | 23.7°C | -3.9°C | 82 mm | 80% | 0.7 m/s | 4.2 |
| 1999 | 15.5°C | 9.0°C | 2.4°C | 22.8°C | -2.2°C | 71 mm | 77% | 0.6 m/s | 4.9 |
| 1998 | 15.7°C | 9.9°C | 4.0°C | 22.4°C | -2.9°C | 141 mm | 80% | 0.6 m/s | 4.9 |
| 1997 | 13.7°C | 7.6°C | 1.6°C | 20.9°C | -4.9°C | 39 mm | 76% | 0.7 m/s | 5.2 |
| 1996 | 14.1°C | 8.2°C | 2.4°C | 23.6°C | -3.5°C | 150 mm | 82% | 0.7 m/s | 4.5 |
| 1995 | 14.1°C | 7.5°C | 0.9°C | 24.1°C | -5.8°C | 61 mm | 75% | 0.6 m/s | 5 |
| 1994 | 16.9°C | 10.5°C | 4.1°C | 26.0°C | -4.2°C | 89 mm | 82% | 0.6 m/s | 5.2 |
| 1993 | 14.6°C | 8.6°C | 2.5°C | 21.8°C | -3.6°C | 189 mm | 83% | 0.7 m/s | 4.4 |
| 1992 | 14.0°C | 8.2°C | 2.3°C | 21.8°C | -4.3°C | 52 mm | 80% | 0.6 m/s | 4.4 |
| 1991 | 15.7°C | 9.9°C | 4.1°C | 25.8°C | -4.1°C | 73 mm | 82% | 0.6 m/s | 4.2 |
| 1990 | 15.1°C | 9.3°C | 3.5°C | 30.4°C | -4.8°C | 80 mm | 81% | 0.6 m/s | 4.4 |
| 1989 | 13.8°C | 7.6°C | 1.4°C | 23.3°C | -4.6°C | 40 mm | 77% | 0.6 m/s | 4.8 |
| 1988 | 13.5°C | 7.6°C | 1.8°C | 20.0°C | -3.3°C | 62 mm | 80% | 0.7 m/s | 4.6 |
| 1987 | 14.6°C | 9.1°C | 3.6°C | 22.6°C | -3.6°C | 105 mm | 83% | 0.6 m/s | 4.3 |
| 1986 | 14.5°C | 8.7°C | 3.0°C | 23.5°C | -2.6°C | 112 mm | 82% | 0.6 m/s | 4.5 |
| 1985 | 17.0°C | 10.6°C | 4.2°C | 28.9°C | -6.0°C | 22 mm | 75% | 0.6 m/s | 4.8 |
| 1984 | 13.5°C | 7.9°C | 2.3°C | 22.2°C | -3.6°C | 124 mm | 85% | 0.6 m/s | 4.3 |
| 1983 🌧️ | 13.3°C | 8.1°C | 3.0°C | 24.8°C | -3.7°C | 242 mm | 84% | 0.7 m/s | — |
| 1982 ❄️ | 13.3°C | 6.6°C | -0.1°C | 22.7°C | -9.4°C | 133 mm | 77% | 0.8 m/s | — |
| 1981 | 16.6°C | 9.6°C | 2.7°C | 24.6°C | -5.1°C | 102 mm | 77% | 0.7 m/s | — |
Actual recorded April data for each year, 1981–2025 — sourced from NASA POWER.
The average high in April is around 15.4°C with lows near 3.2°C (mean 9.3°C), based on 45 years of NASA POWER data.
April averages 98 mm of rainfall in Allentown, about average for rainfall. The wettest on record was 242 mm in 1983.
The hottest April reached 32.1°C in 2002. The coldest dipped to -9.4°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average April temperatures have risen by about 1.8°C. Daytime highs moved from 14.7°C to 16.6°C and overnight lows from 2.4°C to 4.2°C over the same span.
April is one of the cooler months of the year in Allentown and about average for rainfall, so plan for around 15.4°C daytime highs and 3.2°C at night.
Not quite — April is the 6th coolest month in Allentown, averaging 9.3°C.
For April in Allentown, pack warm layers and a jacket for chilly mornings, with typical highs of 15.4°C and lows of 3.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in April averages 79% — quite humid.
Average wind speed in April is 0.6 m/s. The windiest April on record averaged 0.8 m/s (1982).
The wettest April on record was 1983 with 242 mm. On average, April sees 98 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 April, 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 April specifically, along with year-by-year records and how the month has changed over the decades.
