Grafton weather by month
What a typical year looks like in Grafton, Wisconsin: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at GERMANTOWN WASTEWATER UTILITY, 17 km from Grafton; records cover 1944–2026.
The year at a glance
- Precipitation a year
- 34.4 in873 mm
- Snow a year
- 54 in138 cm
- Last spring freeze
- May 3
- First fall freeze
- Oct 4
- Heating degree days
- 7,448
- Cooling degree days
- 494
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −9°−23° (heating, 99%) and 91°33° (cooling, 1%).
Month by month
Grafton in January
Highs average 27°−3° and lows 11°−11°, with 1.6 in40 mm of precipitation and 17 in42 cm of snow in a typical January.
- Record high
- 58°14° (2013)
- Record low
- −40° (1982)
- Heating degree days
- 1416
- Cooling degree days
- 0
Grafton in February
Highs average 31°−1° and lows 14°−10°, with 1.4 in37 mm of precipitation and 16 in41 cm of snow in a typical February.
- Record high
- 72°22° (2024)
- Record low
- −28°−33° (1996)
- Heating degree days
- 1201
- Cooling degree days
- 0
Grafton in March
Highs average 42°5° and lows 24°−5°, with 1.9 in48 mm of precipitation and 7 in17 cm of snow in a typical March.
- Record high
- 83°28° (1986)
- Record low
- −20°−29° (1962)
- Heating degree days
- 999
- Cooling degree days
- 0
Grafton in April
Highs average 54°12° and lows 34°1°, with 3.8 in98 mm of precipitation and 2 in5.1 cm of snow in a typical April.
- Record high
- 89°32° (1980)
- Record low
- 7°−14° (1979)
- Heating degree days
- 626
- Cooling degree days
- 2
Grafton in May
Highs average 66°19° and lows 45°7°, with 4 in100 mm of precipitation and 0.3 in0.8 cm of snow in a typical May.
- Record high
- 93°34° (2018)
- Record low
- 20°−7° (1966)
- Heating degree days
- 315
- Cooling degree days
- 24
Grafton in June
Highs average 76°25° and lows 54°12°, with 4.4 in111 mm of precipitation in a typical June.
- Record high
- 99°37° (1988)
- Record low
- 23°−5° (1990)
- Heating degree days
- 84
- Cooling degree days
- 94
Grafton in July
Highs average 81°27° and lows 60°15°, with 3.9 in100 mm of precipitation in a typical July.
- Record high
- 104°40° (2012)
- Record low
- 36°2° (1993)
- Heating degree days
- 21
- Cooling degree days
- 181
Grafton in August
Highs average 79°26° and lows 58°14°, with 3.8 in97 mm of precipitation in a typical August.
- Record high
- 102°39° (1988)
- Record low
- 33°1° (1992)
- Heating degree days
- 32
- Cooling degree days
- 138
Grafton in September
Highs average 72°22° and lows 50°10°, with 3.2 in82 mm of precipitation in a typical September.
- Record high
- 99°37° (1953)
- Record low
- 22°−6° (1993)
- Heating degree days
- 169
- Cooling degree days
- 50
Grafton in OctoberThis month
Highs average 59°15° and lows 39°4°, with 2.6 in67 mm of precipitation and 0.3 in0.8 cm of snow in a typical October.
- Record high
- 89°32° (1963)
- Record low
- 8°−13° (1993)
- Heating degree days
- 502
- Cooling degree days
- 5
Grafton in November
Highs average 45°7° and lows 28°−2°, with 2 in51 mm of precipitation and 2.4 in6.1 cm of snow in a typical November.
- Record high
- 77°25° (1950)
- Record low
- −15°−26° (1976)
- Heating degree days
- 857
- Cooling degree days
- 0
Grafton in December
Highs average 33°1° and lows 18°−8°, with 1.7 in44 mm of precipitation and 10 in26 cm of snow in a typical December.
- Record high
- 67°19° (2001)
- Record low
- −25°−32° (1983)
- Heating degree days
- 1226
- Cooling degree days
- 0