April is one of the cooler months of the year in Williamsport, with average highs near 12.8°C and lows around 0.9°C (mean 6.9°C). It is about average for rainfall, averaging 90 mm of rainfall and 80% relative humidity across the period.
April is one of the cooler months of the year in Williamsport. Across 45 years of records, the warmest April in Williamsport was 2017 — when the month averaged 10.1°C — while the coldest was 1982 at 4°C. Typical April days reach 12.8°C with nights near 0.9°C. The long-term trend is warming, about 0.3°C per decade.
April is about average for rainfall in Williamsport, averaging 90 mm of rainfall. The wettest April on record was 2011 with 217 mm, while the driest was 1989 at 29 mm.
Relative humidity in Williamsport during April averages 80%. The most humid April was 2011 at 87%, and the least humid was 2025 at 74%.
April receives about 4.5 kWh/m²/day of solar energy in Williamsport. The sunniest Aprils were 2005 and 2010 at 5.3 kWh/m²/day, and the cloudiest was 2011 at 3.4.
Average wind speed in Williamsport during April is 0.1 m/s. The windiest Aprils were 2020, 2023 and 2024, among others at 0.2 m/s, while the calmest were 2021, 2022 and 2025, among others at 0.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 6.2°C | 6.5°C | 7.2°C | 7.1°C | 7.4°C | +1.2°C |
| Avg High | 12.1°C | 12.4°C | 13.2°C | 13.2°C | 13.4°C | +1.3°C |
| Avg Low | 0.3°C | 0.6°C | 1.2°C | 1.1°C | 1.5°C | +1.2°C |
| Avg Rain | 87 mm | 95 mm | 80 mm | 93 mm | 97 mm | +10 mm |
April temperatures in Williamsport have risen by about 1.7°C between 1981–1985 and 2021–2025.
April has ranged from a record low of -12.6°C (1982) to a record high of 28.2°C (2009).
Rainfall in April is about average for rainfall, averaging 90 mm, with a wettest year of 217 mm.
A good time to visit Williamsport
April is a good time to visit Williamsport, with days averaging 12.8°C and nights around 0.9°C (mean 6.9°C, cooler than Williamsport's yearly average) and higher rainfall. July and August 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 | 14.2°C | 8.1°C | 1.9°C | 24.9°C | -5.7°C | 77 mm | 74% | 0.1 m/s | 4.5 |
| 2024 | 14.4°C | 8.5°C | 2.7°C | 25.9°C | -3.5°C | 126 mm | 82% | 0.2 m/s | 4.1 |
| 2023 | 15.7°C | 9.1°C | 2.6°C | 28.2°C | -5.9°C | 97 mm | 77% | 0.2 m/s | 4.8 |
| 2022 | 11.8°C | 5.9°C | 0.0°C | 24.4°C | -5.0°C | 75 mm | 79% | 0.1 m/s | 4.6 |
| 2021 | 13.7°C | 7.8°C | 1.9°C | 23.5°C | -6.1°C | 78 mm | 78% | 0.1 m/s | 4.6 |
| 2020 | 10.7°C | 5.2°C | -0.3°C | 18.4°C | -4.6°C | 126 mm | 79% | 0.2 m/s | 4.1 |
| 2019 | 14.0°C | 8.1°C | 2.2°C | 20.5°C | -6.3°C | 110 mm | 82% | 0.2 m/s | 4.2 |
| 2018 | 9.5°C | 4.2°C | -1.1°C | 20.8°C | -7.1°C | 81 mm | 79% | 0.2 m/s | 4.2 |
| 2017 🔥 | 16.2°C | 10.1°C | 4.1°C | 23.1°C | -3.8°C | 98 mm | 81% | 0.1 m/s | 4.6 |
| 2016 | 12.0°C | 5.7°C | -0.7°C | 22.0°C | -8.7°C | 54 mm | 76% | 0.2 m/s | 4.8 |
| 2015 | 13.2°C | 6.8°C | 0.4°C | 21.4°C | -5.5°C | 104 mm | 78% | 0.1 m/s | 4.5 |
| 2014 | 12.1°C | 5.7°C | -0.6°C | 21.4°C | -7.5°C | 91 mm | 80% | 0.1 m/s | 4.7 |
| 2013 | 12.9°C | 7.0°C | 1.0°C | 22.4°C | -8.5°C | 71 mm | 78% | 0.1 m/s | 4.9 |
| 2012 | 12.8°C | 6.6°C | 0.4°C | 25.0°C | -4.7°C | 53 mm | 76% | 0.1 m/s | 5.2 |
| 2011 🌧️ | 12.8°C | 7.6°C | 2.4°C | 23.3°C | -4.3°C | 217 mm | 87% | 0.1 m/s | 3.4 |
| 2010 | 16.3°C | 9.5°C | 2.6°C | 23.8°C | -2.1°C | 54 mm | 75% | 0.2 m/s | 5.3 |
| 2009 | 13.7°C | 7.7°C | 1.6°C | 28.2°C | -5.0°C | 68 mm | 77% | 0.2 m/s | 4.7 |
| 2008 | 14.9°C | 8.7°C | 2.4°C | 24.5°C | -5.0°C | 64 mm | 80% | 0.2 m/s | 5.2 |
| 2007 | 9.9°C | 5.0°C | 0.1°C | 21.9°C | -6.7°C | 90 mm | 81% | 0.1 m/s | 4 |
| 2006 | 14.2°C | 7.6°C | 1.0°C | 22.4°C | -5.1°C | 73 mm | 78% | 0.1 m/s | 5.2 |
| 2005 | 13.9°C | 7.5°C | 1.1°C | 23.1°C | -4.0°C | 104 mm | 80% | 0.1 m/s | 5.3 |
| 2004 | 12.9°C | 7.3°C | 1.7°C | 22.4°C | -6.5°C | 96 mm | 81% | 0.1 m/s | 4.3 |
| 2003 | 12.0°C | 6.2°C | 0.3°C | 23.0°C | -8.1°C | 63 mm | 82% | 0.1 m/s | 4.2 |
| 2002 | 14.0°C | 8.1°C | 2.2°C | 27.7°C | -5.3°C | 74 mm | 78% | 0.1 m/s | 4.3 |
| 2001 | 14.3°C | 7.6°C | 1.0°C | 25.9°C | -5.2°C | 48 mm | 78% | 0.2 m/s | 4.7 |
| 2000 | 12.3°C | 6.5°C | 0.7°C | 21.0°C | -4.9°C | 119 mm | 81% | 0.1 m/s | 4 |
| 1999 | 12.9°C | 6.6°C | 0.2°C | 19.1°C | -4.8°C | 68 mm | 77% | 0.1 m/s | 4.9 |
| 1998 | 13.3°C | 7.4°C | 1.4°C | 19.2°C | -4.9°C | 131 mm | 79% | 0.2 m/s | 4.6 |
| 1997 | 11.0°C | 5.2°C | -0.6°C | 19.8°C | -7.6°C | 29 mm | 77% | 0.2 m/s | 5.1 |
| 1996 | 11.2°C | 5.6°C | -0.1°C | 20.6°C | -6.2°C | 138 mm | 83% | 0.1 m/s | 4.1 |
| 1995 | 10.7°C | 4.6°C | -1.6°C | 19.9°C | -8.1°C | 68 mm | 76% | 0.1 m/s | 4.9 |
| 1994 | 14.0°C | 7.7°C | 1.3°C | 23.9°C | -5.2°C | 95 mm | 82% | 0.1 m/s | 5.1 |
| 1993 | 12.2°C | 6.4°C | 0.6°C | 20.3°C | -5.2°C | 203 mm | 84% | 0.1 m/s | 3.9 |
| 1992 | 11.4°C | 5.9°C | 0.4°C | 20.1°C | -6.2°C | 71 mm | 81% | 0.1 m/s | 4.2 |
| 1991 | 13.8°C | 8.3°C | 2.8°C | 22.9°C | -4.8°C | 74 mm | 83% | 0.1 m/s | 4.2 |
| 1990 | 13.1°C | 7.3°C | 1.5°C | 26.6°C | -5.5°C | 70 mm | 81% | 0.1 m/s | 4.3 |
| 1989 | 11.6°C | 5.2°C | -1.1°C | 21.0°C | -5.5°C | 29 mm | 76% | 0.1 m/s | 4.9 |
| 1988 | 11.4°C | 5.7°C | -0.1°C | 19.0°C | -5.5°C | 58 mm | 80% | 0.1 m/s | 4.4 |
| 1987 | 12.7°C | 7.5°C | 2.3°C | 24.4°C | -5.7°C | 95 mm | 83% | 0.1 m/s | 4.3 |
| 1986 | 12.5°C | 6.8°C | 1.0°C | 21.7°C | -4.7°C | 99 mm | 82% | 0.1 m/s | 4.7 |
| 1985 | 14.5°C | 8.5°C | 2.4°C | 26.5°C | -6.1°C | 32 mm | 79% | 0.2 m/s | 4.8 |
| 1984 | 11.1°C | 5.9°C | 0.7°C | 21.2°C | -6.5°C | 115 mm | 85% | 0.1 m/s | 4.2 |
| 1983 | 10.4°C | 5.4°C | 0.3°C | 21.9°C | -5.2°C | 194 mm | 85% | 0.1 m/s | — |
| 1982 ❄️ | 10.6°C | 4.0°C | -2.5°C | 21.2°C | -12.6°C | 68 mm | 77% | 0.2 m/s | — |
| 1981 | 14.0°C | 7.1°C | 0.1°C | 20.7°C | -6.1°C | 92 mm | 78% | 0.2 m/s | — |
Actual recorded April data for each year, 1981–2025 — sourced from NASA POWER.
The average high in April is around 12.8°C with lows near 0.9°C (mean 6.9°C), based on 45 years of NASA POWER data.
April averages 90 mm of rainfall in Williamsport, about average for rainfall. The wettest on record was 217 mm in 2011.
The hottest April reached 28.2°C in 2009. The coldest dipped to -12.6°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average April temperatures have risen by about 1.7°C. Daytime highs moved from 12.1°C to 14°C and overnight lows from 0.2°C to 1.8°C over the same span.
April is one of the cooler months of the year in Williamsport and about average for rainfall, so plan for around 12.8°C daytime highs and 0.9°C at night.
Not quite — April is the 6th coolest month in Williamsport, averaging 6.9°C.
For April in Williamsport, pack warm layers and a jacket for chilly mornings, with typical highs of 12.8°C and lows of 0.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in April averages 80% — quite humid.
Average wind speed in April is 0.1 m/s. The windiest April on record averaged 0.2 m/s (1981).
The wettest April on record was 2011 with 217 mm. On average, April sees 90 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 Williamsport 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.
