Merrimac weather by month
What a typical year looks like in Merrimac, Wisconsin: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at BARABOO WWTP, 12 km from Merrimac; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 38.9 in988 mm
- Snow a year
- 43 in108 cm
- Last spring freeze
- May 17
- First fall freeze
- Sep 29
- Heating degree days
- 7,292
- Cooling degree days
- 615
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −15°−26° (heating, 99%) and 92°33° (cooling, 1%).
Month by month
Merrimac in January
Highs average 28°−2° and lows 10°−12°, with 1.4 in34 mm of precipitation and 11 in29 cm of snow in a typical January.
- Record high
- 60°16° (2025)
- Record low
- −45°−43° (1951)
- Heating degree days
- 1440
- Cooling degree days
- 0
Merrimac in February
Highs average 32°0° and lows 13°−11°, with 1.4 in35 mm of precipitation and 10 in26 cm of snow in a typical February.
- Record high
- 72°22° (2024)
- Record low
- −41° (1996)
- Heating degree days
- 1194
- Cooling degree days
- 0
Merrimac in March
Highs average 44°7° and lows 23°−5°, with 2.2 in56 mm of precipitation and 6 in15 cm of snow in a typical March.
- Record high
- 84°29° (1986)
- Record low
- −34°−37° (1962)
- Heating degree days
- 974
- Cooling degree days
- 1
Merrimac in April
Highs average 57°14° and lows 34°1°, with 4.2 in106 mm of precipitation and 2.6 in6.6 cm of snow in a typical April.
- Record high
- 92°33° (1980)
- Record low
- −2°−19° (1982)
- Heating degree days
- 584
- Cooling degree days
- 3
Merrimac in May
Highs average 70°21° and lows 46°8°, with 4.3 in109 mm of precipitation in a typical May.
- Record high
- 96°36° (2018)
- Record low
- 19°−7° (1996)
- Heating degree days
- 257
- Cooling degree days
- 37
Merrimac in June
Highs average 79°26° and lows 56°13°, with 5.6 in142 mm of precipitation in a typical June.
- Record high
- 102°39° (1988)
- Record low
- 31°−1° (1982)
- Heating degree days
- 54
- Cooling degree days
- 131
Merrimac in July
Highs average 83°28° and lows 60°16°, with 4.8 in122 mm of precipitation in a typical July.
- Record high
- 103°39° (2012)
- Record low
- 38°3° (1996)
- Heating degree days
- 13
- Cooling degree days
- 213
Merrimac in August
Highs average 81°27° and lows 58°14°, with 4.5 in115 mm of precipitation in a typical August.
- Record high
- 102°39° (1988)
- Record low
- 34°1° (1986)
- Heating degree days
- 28
- Cooling degree days
- 160
Merrimac in September
Highs average 74°23° and lows 50°10°, with 3.9 in98 mm of precipitation in a typical September.
- Record high
- 99°37° (1955)
- Record low
- 20°−7° (1949)
- Heating degree days
- 161
- Cooling degree days
- 62
Merrimac in OctoberThis month
Highs average 61°16° and lows 38°4°, with 2.9 in74 mm of precipitation and 0.4 in1 cm of snow in a typical October.
- Record high
- 92°33° (1963)
- Record low
- 10°−12° (1988)
- Heating degree days
- 490
- Cooling degree days
- 8
Merrimac in November
Highs average 46°8° and lows 28°−2°, with 2.2 in56 mm of precipitation and 2.1 in5.3 cm of snow in a typical November.
- Record high
- 76°24° (1964)
- Record low
- −17°−27° (1977)
- Heating degree days
- 854
- Cooling degree days
- 0
Merrimac in December
Highs average 33°1° and lows 17°−9°, with 1.7 in43 mm of precipitation and 10 in26 cm of snow in a typical December.
- Record high
- 68°20° (2021)
- Record low
- −35°−37° (1983)
- Heating degree days
- 1243
- Cooling degree days
- 0