Mermentau weather by month
What a typical year looks like in Mermentau, Louisiana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Jennings, 8 km from Mermentau; records cover 1897–2026.
The year at a glance
- Precipitation a year
- 63.5 in1613 mm
- Snow a year
- Rare
- Last spring freeze
- Feb 13
- First fall freeze
- Dec 2
- Heating degree days
- 1,616
- Cooling degree days
- 2,665
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 27°−3° (heating, 99%) and 97°36° (cooling, 1%).
Month by month
Mermentau in January
Highs average 60°16° and lows 42°5°, with 6.3 in160 mm of precipitation in a typical January.
- Record high
- 83°28° (1898)
- Record low
- 7°−14° (2025)
- Heating degree days
- 447
- Cooling degree days
- 8
Mermentau in February
Highs average 64°18° and lows 45°7°, with 4.3 in108 mm of precipitation in a typical February.
- Record high
- 87°31° (1917)
- Record low
- 9°−13° (1899)
- Heating degree days
- 308
- Cooling degree days
- 14
Mermentau in March
Highs average 71°22° and lows 52°11°, with 3.8 in96 mm of precipitation in a typical March.
- Record high
- 92°33° (1946)
- Record low
- 20°−7° (2002)
- Heating degree days
- 171
- Cooling degree days
- 50
Mermentau in April
Highs average 77°25° and lows 58°14°, with 4.8 in122 mm of precipitation in a typical April.
- Record high
- 97°36° (1915)
- Record low
- 32°0° (1920)
- Heating degree days
- 54
- Cooling degree days
- 128
Mermentau in May
Highs average 84°29° and lows 66°19°, with 5.5 in140 mm of precipitation in a typical May.
- Record high
- 100°38° (1911)
- Record low
- 39°4° (1913)
- Heating degree days
- 4
- Cooling degree days
- 308
Mermentau in June
Highs average 89°31° and lows 72°22°, with 6.6 in168 mm of precipitation in a typical June.
- Record high
- 104°40° (1911)
- Record low
- 46°8° (1903)
- Heating degree days
- 0
- Cooling degree days
- 457
Mermentau in July
Highs average 90°32° and lows 74°23°, with 5.4 in136 mm of precipitation in a typical July.
- Record high
- 105°41° (1901)
- Record low
- 59°15° (1898)
- Heating degree days
- 0
- Cooling degree days
- 525
Mermentau in August
Highs average 91°33° and lows 73°23°, with 6.8 in173 mm of precipitation in a typical August.
- Record high
- 107°42° (2023)
- Record low
- 59°15° (1931)
- Heating degree days
- 0
- Cooling degree days
- 530
Mermentau in September
Highs average 88°31° and lows 69°21°, with 5.8 in147 mm of precipitation in a typical September.
- Record high
- 107°42° (2000)
- Record low
- 43°6° (1909)
- Heating degree days
- 1
- Cooling degree days
- 401
Mermentau in OctoberThis month
Highs average 80°27° and lows 59°15°, with 4.7 in120 mm of precipitation in a typical October.
- Record high
- 98°37° (1915)
- Record low
- 27°−3° (1917)
- Heating degree days
- 42
- Cooling degree days
- 183
Mermentau in November
Highs average 70°21° and lows 49°10°, with 4.9 in123 mm of precipitation in a typical November.
- Record high
- 95°35° (1901)
- Record low
- 22°−6° (1938)
- Heating degree days
- 202
- Cooling degree days
- 44
Mermentau in December
Highs average 63°17° and lows 44°6°, with 4.7 in120 mm of precipitation and 0.1 in0.3 cm of snow in a typical December.
- Record high
- 89°32° (1917)
- Record low
- 10°−12° (1989)
- Heating degree days
- 387
- Cooling degree days
- 17