Forsyth weather by month
What a typical year looks like in Forsyth, Montana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Forsyth, 1 km from Forsyth; records cover 1975–2026.
The year at a glance
- Precipitation a year
- 16 in406 mm
- Snow a year
- 35 in88 cm
- Last spring freeze
- May 12
- First fall freeze
- Sep 28
- Heating degree days
- 7,248
- Cooling degree days
- 620
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −17°−27° (heating, 99%) and 100°38° (cooling, 1%).
Month by month
Forsyth in January
Highs average 34°1° and lows 10°−12°, with 0.61 in15 mm of precipitation and 8 in20 cm of snow in a typical January.
- Record high
- 70°21° (1992)
- Record low
- −38°−39° (1996)
- Heating degree days
- 1334
- Cooling degree days
- 0
Forsyth in February
Highs average 38°3° and lows 14°−10°, with 0.58 in15 mm of precipitation and 7 in19 cm of snow in a typical February.
- Record high
- 73°23° (1992)
- Record low
- −38°−39° (1996)
- Heating degree days
- 1099
- Cooling degree days
- 0
Forsyth in March
Highs average 49°10° and lows 23°−5°, with 0.94 in24 mm of precipitation and 4 in10 cm of snow in a typical March.
- Record high
- 86°30° (2004)
- Record low
- −31°−35° (2019)
- Heating degree days
- 890
- Cooling degree days
- 0
Forsyth in April
Highs average 59°15° and lows 33°0°, with 1.9 in47 mm of precipitation and 2.8 in7.1 cm of snow in a typical April.
- Record high
- 91°33° (1980)
- Record low
- 1°−17° (2008)
- Heating degree days
- 569
- Cooling degree days
- 0
Forsyth in May
Highs average 69°20° and lows 43°6°, with 2.9 in74 mm of precipitation and 0.4 in1 cm of snow in a typical May.
- Record high
- 99°37° (1980)
- Record low
- 19°−7° (2004)
- Heating degree days
- 298
- Cooling degree days
- 13
Forsyth in June
Highs average 79°26° and lows 52°11°, with 2.5 in65 mm of precipitation in a typical June.
- Record high
- 108°42° (2021)
- Record low
- 34°1° (1979)
- Heating degree days
- 78
- Cooling degree days
- 86
Forsyth in July
Highs average 88°31° and lows 58°15°, with 1.4 in35 mm of precipitation in a typical July.
- Record high
- 112°44° (2026)
- Record low
- 41°5° (1987)
- Heating degree days
- 9
- Cooling degree days
- 260
Forsyth in August
Highs average 87°30° and lows 56°13°, with 1.2 in30 mm of precipitation in a typical August.
- Record high
- 106°41° (2026)
- Record low
- 32°0° (1992)
- Heating degree days
- 24
- Cooling degree days
- 215
Forsyth in September
Highs average 75°24° and lows 46°8°, with 1.4 in35 mm of precipitation and 0.1 in0.3 cm of snow in a typical September.
- Record high
- 105°41° (2022)
- Record low
- 19°−7° (1985)
- Heating degree days
- 179
- Cooling degree days
- 44
Forsyth in OctoberThis month
Highs average 60°16° and lows 34°1°, with 1.4 in35 mm of precipitation and 1.5 in3.8 cm of snow in a typical October.
- Record high
- 93°34° (1997)
- Record low
- −11°−24° (1991)
- Heating degree days
- 564
- Cooling degree days
- 2
Forsyth in November
Highs average 46°8° and lows 22°−6°, with 0.66 in17 mm of precipitation and 4 in10 cm of snow in a typical November.
- Record high
- 82°28° (1999)
- Record low
- −27°−33° (1977)
- Heating degree days
- 933
- Cooling degree days
- 0
Forsyth in December
Highs average 35°2° and lows 13°−11°, with 0.58 in15 mm of precipitation and 7 in18 cm of snow in a typical December.
- Record high
- 70°21° (1995)
- Record low
- −44°−42° (1989)
- Heating degree days
- 1271
- Cooling degree days
- 0