West Mifflin weather by month
What a typical year looks like in West Mifflin, Pennsylvania: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at PITTSBURGH ALLEGHENY COUNTY AP, 1 km from West Mifflin; records cover 1935–2026.
The year at a glance
- Precipitation a year
- 41.3 in1050 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 16
- First fall freeze
- Oct 25
- Heating degree days
- 5,406
- Cooling degree days
- 825
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 5°−15° (heating, 99%) and 91°33° (cooling, 1%).
Month by month
West Mifflin in January
Highs average 37°3° and lows 22°−5°, with 3.1 in78 mm of precipitation in a typical January.
- Record high
- 75°24° (1950)
- Record low
- −16°−27° (1936)
- Heating degree days
- 1102
- Cooling degree days
- 0
West Mifflin in February
Highs average 40°4° and lows 24°−4°, with 2.6 in65 mm of precipitation in a typical February.
- Record high
- 77°25° (2017)
- Record low
- −8°−22° (1936)
- Heating degree days
- 921
- Cooling degree days
- 0
West Mifflin in March
Highs average 49°10° and lows 31°0°, with 3.2 in82 mm of precipitation in a typical March.
- Record high
- 84°29° (2026)
- Record low
- −1°−18° (1943)
- Heating degree days
- 765
- Cooling degree days
- 1
West Mifflin in April
Highs average 63°17° and lows 42°5°, with 3.4 in86 mm of precipitation in a typical April.
- Record high
- 87°31° (1941)
- Record low
- 15°−9° (1950)
- Heating degree days
- 396
- Cooling degree days
- 11
West Mifflin in May
Highs average 72°22° and lows 52°11°, with 4.1 in104 mm of precipitation in a typical May.
- Record high
- 93°34° (1942)
- Record low
- 28°−2° (2020)
- Heating degree days
- 157
- Cooling degree days
- 59
West Mifflin in June
Highs average 79°26° and lows 60°16°, with 4.6 in116 mm of precipitation in a typical June.
- Record high
- 99°37° (2012)
- Record low
- 38°3° (1945)
- Heating degree days
- 26
- Cooling degree days
- 161
West Mifflin in July
Highs average 83°28° and lows 64°18°, with 3.9 in100 mm of precipitation in a typical July.
- Record high
- 102°39° (1936)
- Record low
- 46°8° (1943)
- Heating degree days
- 2
- Cooling degree days
- 267
West Mifflin in August
Highs average 81°27° and lows 63°17°, with 3.8 in97 mm of precipitation in a typical August.
- Record high
- 99°37° (1948)
- Record low
- 46°8° (1935)
- Heating degree days
- 6
- Cooling degree days
- 224
West Mifflin in September
Highs average 75°24° and lows 56°13°, with 3.5 in90 mm of precipitation in a typical September.
- Record high
- 96°36° (1952)
- Record low
- 34°1° (1942)
- Heating degree days
- 78
- Cooling degree days
- 88
West Mifflin in OctoberThis month
Highs average 63°17° and lows 45°7°, with 3.1 in78 mm of precipitation in a typical October.
- Record high
- 89°32° (1951)
- Record low
- 25°−4° (1940)
- Heating degree days
- 349
- Cooling degree days
- 14
West Mifflin in November
Highs average 51°11° and lows 35°2°, with 3 in77 mm of precipitation in a typical November.
- Record high
- 80°27° (1948)
- Record low
- 7°−14° (1950)
- Heating degree days
- 654
- Cooling degree days
- 0
West Mifflin in December
Highs average 41°5° and lows 28°−2°, with 3 in77 mm of precipitation in a typical December.
- Record high
- 73°23° (2001)
- Record low
- −5°−21° (1935)
- Heating degree days
- 950
- Cooling degree days
- 0