St. Marie weather by month
What a typical year looks like in St. Marie, Montana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Glasgow International Airport, 23 km from St. Marie; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 13.4 in341 mm
- Snow a year
- 41 in103 cm
- Last spring freeze
- May 11
- First fall freeze
- Sep 22
- Heating degree days
- 8,245
- Cooling degree days
- 584
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −23°−31° (heating, 99%) and 98°37° (cooling, 1%).
Month by month
St. Marie in January
Highs average 24°−5° and lows 6°−15°, with 0.44 in11 mm of precipitation and 10 in25 cm of snow in a typical January.
- Record high
- 62°17° (1919)
- Record low
- −56°−49° (1916)
- Heating degree days
- 1561
- Cooling degree days
- 0
St. Marie in February
Highs average 28°−2° and lows 9°−13°, with 0.35 in8.9 mm of precipitation and 6 in16 cm of snow in a typical February.
- Record high
- 74°23° (1932)
- Record low
- −59°−51° (1936)
- Heating degree days
- 1296
- Cooling degree days
- 0
St. Marie in March
Highs average 42°5° and lows 21°−6°, with 0.47 in12 mm of precipitation and 6 in14 cm of snow in a typical March.
- Record high
- 81°27° (1928)
- Record low
- −45°−43° (1897)
- Heating degree days
- 1036
- Cooling degree days
- 0
St. Marie in April
Highs average 57°14° and lows 33°0°, with 1 in26 mm of precipitation and 2.5 in6.4 cm of snow in a typical April.
- Record high
- 93°34° (1952)
- Record low
- −19°−28° (1899)
- Heating degree days
- 607
- Cooling degree days
- 0
St. Marie in May
Highs average 68°20° and lows 43°6°, with 2.2 in56 mm of precipitation and 0.9 in2.3 cm of snow in a typical May.
- Record high
- 102°39° (1948)
- Record low
- 15°−9° (1929)
- Heating degree days
- 310
- Cooling degree days
- 16
St. Marie in June
Highs average 76°25° and lows 53°12°, with 2.8 in72 mm of precipitation in a typical June.
- Record high
- 110°43° (1933)
- Record low
- 24°−4° (1919)
- Heating degree days
- 88
- Cooling degree days
- 73
St. Marie in July
Highs average 86°30° and lows 59°15°, with 2 in50 mm of precipitation in a typical July.
- Record high
- 113°45° (1900)
- Record low
- 34°1° (1904)
- Heating degree days
- 14
- Cooling degree days
- 230
St. Marie in August
Highs average 85°29° and lows 57°14°, with 1.3 in32 mm of precipitation in a typical August.
- Record high
- 108°42° (1926)
- Record low
- 28°−2° (1928)
- Heating degree days
- 30
- Cooling degree days
- 216
St. Marie in September
Highs average 73°23° and lows 47°8°, with 1.1 in27 mm of precipitation in a typical September.
- Record high
- 106°41° (2022)
- Record low
- 14°−10° (1928)
- Heating degree days
- 200
- Cooling degree days
- 47
St. Marie in OctoberThis month
Highs average 57°14° and lows 34°1°, with 0.92 in23 mm of precipitation and 1.5 in3.8 cm of snow in a typical October.
- Record high
- 96°36° (1943)
- Record low
- −8°−22° (1905)
- Heating degree days
- 618
- Cooling degree days
- 2
St. Marie in November
Highs average 40°4° and lows 21°−6°, with 0.49 in12 mm of precipitation and 6 in15 cm of snow in a typical November.
- Record high
- 79°26° (1999)
- Record low
- −41° (1896)
- Heating degree days
- 1042
- Cooling degree days
- 0
St. Marie in December
Highs average 27°−3° and lows 10°−12°, with 0.43 in11 mm of precipitation and 8 in21 cm of snow in a typical December.
- Record high
- 69°21° (1939)
- Record low
- −47°−44° (1924)
- Heating degree days
- 1443
- Cooling degree days
- 0