Pioneer Junction weather by month
What a typical year looks like in Pioneer Junction, Montana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Libby Dam (base), 18 km from Pioneer Junction; records cover 1986–2026.
The year at a glance
- Precipitation a year
- 17.1 in433 mm
- Snow a year
- Rare
- Last spring freeze
- May 18
- First fall freeze
- Sep 29
- Heating degree days
- 7,046
- Cooling degree days
- 292
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −1°−18° (heating, 99%) and 97°36° (cooling, 1%).
Month by month
Pioneer Junction in January
Highs average 35°1° and lows 22°−6°, with 1.5 in38 mm of precipitation in a typical January.
- Record high
- 55°13° (1998)
- Record low
- −27°−33° (2024)
- Heating degree days
- 1145
- Cooling degree days
- 0
Pioneer Junction in February
Highs average 40°4° and lows 22°−6°, with 1.2 in29 mm of precipitation in a typical February.
- Record high
- 67°19° (1995)
- Record low
- −15°−26° (1989)
- Heating degree days
- 965
- Cooling degree days
- 0
Pioneer Junction in March
Highs average 49°9° and lows 26°−3°, with 1.1 in28 mm of precipitation in a typical March.
- Record high
- 76°24° (2004)
- Record low
- −12°−24° (2019)
- Heating degree days
- 856
- Cooling degree days
- 0
Pioneer Junction in April
Highs average 58°14° and lows 32°0°, with 1.2 in31 mm of precipitation in a typical April.
- Record high
- 86°30° (2012)
- Record low
- 10°−12° (1997)
- Heating degree days
- 608
- Cooling degree days
- 0
Pioneer Junction in May
Highs average 68°20° and lows 39°4°, with 1.8 in44 mm of precipitation in a typical May.
- Record high
- 97°36° (1993)
- Record low
- 19°−7° (1999)
- Heating degree days
- 349
- Cooling degree days
- 4
Pioneer Junction in June
Highs average 75°24° and lows 46°8°, with 2.4 in61 mm of precipitation in a typical June.
- Record high
- 106°41° (2021)
- Record low
- 30°−1° (2021)
- Heating degree days
- 167
- Cooling degree days
- 27
Pioneer Junction in July
Highs average 85°30° and lows 50°10°, with 0.85 in22 mm of precipitation in a typical July.
- Record high
- 104°40° (1994)
- Record low
- 26°−3° (1999)
- Heating degree days
- 43
- Cooling degree days
- 130
Pioneer Junction in August
Highs average 85°30° and lows 49°10°, with 0.7 in18 mm of precipitation in a typical August.
- Record high
- 108°42° (2018)
- Record low
- 35°2° (1993)
- Heating degree days
- 46
- Cooling degree days
- 117
Pioneer Junction in September
Highs average 74°23° and lows 42°6°, with 1.1 in28 mm of precipitation in a typical September.
- Record high
- 100°38° (1998)
- Record low
- 22°−6° (1999)
- Heating degree days
- 224
- Cooling degree days
- 14
Pioneer Junction in OctoberThis month
Highs average 57°14° and lows 34°1°, with 1.7 in44 mm of precipitation in a typical October.
- Record high
- 87°31° (1991)
- Record low
- 3°−16° (2002)
- Heating degree days
- 606
- Cooling degree days
- 0
Pioneer Junction in November
Highs average 42°6° and lows 28°−2°, with 1.8 in47 mm of precipitation in a typical November.
- Record high
- 69°21° (1999)
- Record low
- −9°−23° (1993)
- Heating degree days
- 903
- Cooling degree days
- 0
Pioneer Junction in December
Highs average 34°1° and lows 23°−5°, with 1.7 in43 mm of precipitation in a typical December.
- Record high
- 60°16° (2021)
- Record low
- −21°−29° (1990)
- Heating degree days
- 1134
- Cooling degree days
- 0