South Lyon weather by month
What a typical year looks like in South Lyon, Michigan: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at ANN ARBOR U OF MICH, 18 km from South Lyon; records cover 1881–2026.
The year at a glance
- Precipitation a year
- 38.3 in972 mm
- Snow a year
- 61 in156 cm
- Last spring freeze
- Apr 28
- First fall freeze
- Oct 14
- Heating degree days
- 6,500
- Cooling degree days
- 654
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 0°−18° (heating, 99%) and 93°34° (cooling, 1%).
Month by month
South Lyon in January
Highs average 32°0° and lows 16°−9°, with 3 in75 mm of precipitation and 18 in46 cm of snow in a typical January.
- Record high
- 72°22° (1950)
- Record low
- −22°−30° (1994)
- Heating degree days
- 1269
- Cooling degree days
- 0
South Lyon in February
Highs average 35°2° and lows 18°−8°, with 2.5 in64 mm of precipitation and 15 in39 cm of snow in a typical February.
- Record high
- 73°23° (2024)
- Record low
- −23°−31° (1885)
- Heating degree days
- 1076
- Cooling degree days
- 0
South Lyon in March
Highs average 46°8° and lows 25°−4°, with 2.8 in72 mm of precipitation and 8 in21 cm of snow in a typical March.
- Record high
- 85°29° (2012)
- Record low
- −8°−22° (1884)
- Heating degree days
- 909
- Cooling degree days
- 0
South Lyon in April
Highs average 60°15° and lows 36°2°, with 3.4 in87 mm of precipitation and 2.6 in6.6 cm of snow in a typical April.
- Record high
- 88°31° (1899)
- Record low
- 7°−14° (1982)
- Heating degree days
- 526
- Cooling degree days
- 4
South Lyon in May
Highs average 71°22° and lows 47°8°, with 3.8 in98 mm of precipitation in a typical May.
- Record high
- 95°35° (1911)
- Record low
- 24°−4° (1929)
- Heating degree days
- 226
- Cooling degree days
- 40
South Lyon in June
Highs average 80°27° and lows 56°13°, with 3.9 in99 mm of precipitation in a typical June.
- Record high
- 103°39° (1934)
- Record low
- 35°2° (1913)
- Heating degree days
- 44
- Cooling degree days
- 134
South Lyon in July
Highs average 84°29° and lows 60°16°, with 3.5 in89 mm of precipitation in a typical July.
- Record high
- 105°41° (1934)
- Record low
- 37°3° (1888)
- Heating degree days
- 8
- Cooling degree days
- 222
South Lyon in August
Highs average 82°28° and lows 59°15°, with 3.5 in89 mm of precipitation in a typical August.
- Record high
- 104°40° (1918)
- Record low
- 39°4° (1915)
- Heating degree days
- 15
- Cooling degree days
- 178
South Lyon in September
Highs average 75°24° and lows 52°11°, with 3.2 in81 mm of precipitation in a typical September.
- Record high
- 99°37° (1913)
- Record low
- 27°−3° (1899)
- Heating degree days
- 118
- Cooling degree days
- 69
South Lyon in OctoberThis month
Highs average 62°17° and lows 41°5°, with 3 in76 mm of precipitation and 0.1 in0.3 cm of snow in a typical October.
- Record high
- 91°33° (1897)
- Record low
- 19°−7° (1887)
- Heating degree days
- 427
- Cooling degree days
- 7
South Lyon in November
Highs average 48°9° and lows 31°−1°, with 2.8 in72 mm of precipitation and 4 in10 cm of snow in a typical November.
- Record high
- 78°26° (1950)
- Record low
- −3°−19° (2019)
- Heating degree days
- 772
- Cooling degree days
- 0
South Lyon in December
Highs average 36°2° and lows 22°−5°, with 2.8 in70 mm of precipitation and 13 in32 cm of snow in a typical December.
- Record high
- 67°19° (1998)
- Record low
- −17°−27° (2017)
- Heating degree days
- 1110
- Cooling degree days
- 0