Stonybrook weather by month
What a typical year looks like in Stonybrook, Pennsylvania: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Safe Harbor Dam, 22 km from Stonybrook; records cover 1995–2026.
The year at a glance
- Precipitation a year
- 46.3 in1176 mm
- Snow a year
- 21 in54 cm
- Last spring freeze
- Apr 6
- First fall freeze
- Nov 11
- Heating degree days
- 4,908
- Cooling degree days
- 1,164
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 10°−12° (heating, 99%) and 95°35° (cooling, 1%).
Month by month
Stonybrook in January
Highs average 39°4° and lows 25°−4°, with 3.3 in83 mm of precipitation and 6 in15 cm of snow in a typical January.
- Record high
- 67°19° (2007)
- Record low
- 3°−16° (2004)
- Heating degree days
- 1021
- Cooling degree days
- 0
Stonybrook in February
Highs average 41°5° and lows 26°−3°, with 2.7 in68 mm of precipitation and 8 in19 cm of snow in a typical February.
- Record high
- 75°24° (2018)
- Record low
- 1°−17° (1996)
- Heating degree days
- 871
- Cooling degree days
- 0
Stonybrook in March
Highs average 50°10° and lows 33°1°, with 4.1 in103 mm of precipitation and 4 in9 cm of snow in a typical March.
- Record high
- 79°26° (2026)
- Record low
- 8°−13° (2014)
- Heating degree days
- 736
- Cooling degree days
- 0
Stonybrook in April
Highs average 63°17° and lows 44°7°, with 3.5 in90 mm of precipitation in a typical April.
- Record high
- 93°34° (2009)
- Record low
- 27°−3° (1995)
- Heating degree days
- 361
- Cooling degree days
- 12
Stonybrook in May
Highs average 72°22° and lows 53°12°, with 3.9 in99 mm of precipitation in a typical May.
- Record high
- 98°37° (1996)
- Record low
- 30°−1° (2020)
- Heating degree days
- 130
- Cooling degree days
- 60
Stonybrook in June
Highs average 82°28° and lows 63°17°, with 4.6 in116 mm of precipitation in a typical June.
- Record high
- 98°37° (2012)
- Record low
- 46°8° (1996)
- Heating degree days
- 12
- Cooling degree days
- 237
Stonybrook in July
Highs average 87°30° and lows 68°20°, with 4.3 in109 mm of precipitation in a typical July.
- Record high
- 105°41° (2011)
- Record low
- 56°13° (1996)
- Heating degree days
- 0
- Cooling degree days
- 380
Stonybrook in August
Highs average 84°29° and lows 66°19°, with 3.6 in91 mm of precipitation in a typical August.
- Record high
- 100°38° (2002)
- Record low
- 52°11° (2025)
- Heating degree days
- 1
- Cooling degree days
- 320
Stonybrook in September
Highs average 77°25° and lows 60°15°, with 4.9 in124 mm of precipitation in a typical September.
- Record high
- 96°36° (2010)
- Record low
- 43°6° (2020)
- Heating degree days
- 40
- Cooling degree days
- 139
Stonybrook in OctoberThis month
Highs average 65°18° and lows 48°9°, with 4.4 in111 mm of precipitation in a typical October.
- Record high
- 90°32° (2007)
- Record low
- 30°−1° (2007)
- Heating degree days
- 280
- Cooling degree days
- 16
Stonybrook in November
Highs average 53°12° and lows 38°3°, with 3.4 in86 mm of precipitation and 0.5 in1.3 cm of snow in a typical November.
- Record high
- 80°27° (2024)
- Record low
- 18°−8° (2018)
- Heating degree days
- 585
- Cooling degree days
- 0
Stonybrook in December
Highs average 44°6° and lows 30°−1°, with 3.8 in97 mm of precipitation and 4 in9 cm of snow in a typical December.
- Record high
- 73°23° (2006)
- Record low
- 5°−15° (2022)
- Heating degree days
- 871
- Cooling degree days
- 0