Rockport Colony weather by month
What a typical year looks like in Rockport Colony, Montana: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Bynum 4 Sse, 21 km from Rockport Colony; records cover 2011–2026.
The year at a glance
- Precipitation a year
- 15.3 in390 mm
- Snow a year
- Rare
- Last spring freeze
- May 13
- First fall freeze
- Sep 22
- Heating degree days
- 8,039
- Cooling degree days
- 222
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 91°33° (cooling, 1%).
Month by month
Rockport Colony in January
Highs average 36°2° and lows 14°−10°, with 0.6 in15 mm of precipitation in a typical January.
- Record high
- 69°21° (2015)
- Record low
- −34°−37° (2024)
- Heating degree days
- 1236
- Cooling degree days
- 0
Rockport Colony in February
Highs average 36°2° and lows 15°−9°, with 0.43 in11 mm of precipitation in a typical February.
- Record high
- 69°21° (2016)
- Record low
- −29°−34° (2021)
- Heating degree days
- 1106
- Cooling degree days
- 0
Rockport Colony in March
Highs average 44°6° and lows 21°−6°, with 1.1 in27 mm of precipitation in a typical March.
- Record high
- 71°22° (2026)
- Record low
- −22°−30° (2019)
- Heating degree days
- 1018
- Cooling degree days
- 0
Rockport Colony in April
Highs average 51°11° and lows 29°−2°, with 2.1 in54 mm of precipitation in a typical April.
- Record high
- 84°29° (2012)
- Record low
- 2°−17° (2018)
- Heating degree days
- 742
- Cooling degree days
- 0
Rockport Colony in May
Highs average 62°16° and lows 39°4°, with 2.6 in67 mm of precipitation in a typical May.
- Record high
- 88°31° (2025)
- Record low
- 18°−8° (2013)
- Heating degree days
- 460
- Cooling degree days
- 2
Rockport Colony in June
Highs average 71°21° and lows 47°8°, with 2.5 in63 mm of precipitation in a typical June.
- Record high
- 94°34° (2015)
- Record low
- 33°1° (2024)
- Heating degree days
- 209
- Cooling degree days
- 14
Rockport Colony in July
Highs average 80°27° and lows 52°11°, with 1.6 in39 mm of precipitation in a typical July.
- Record high
- 99°37° (2024)
- Record low
- 36°2° (2018)
- Heating degree days
- 59
- Cooling degree days
- 96
Rockport Colony in August
Highs average 79°26° and lows 51°11°, with 1.3 in34 mm of precipitation in a typical August.
- Record high
- 98°37° (2026)
- Record low
- 38°3° (2015)
- Heating degree days
- 78
- Cooling degree days
- 89
Rockport Colony in September
Highs average 70°21° and lows 43°6°, with 1.2 in30 mm of precipitation in a typical September.
- Record high
- 96°36° (2022)
- Record low
- 22°−6° (2019)
- Heating degree days
- 278
- Cooling degree days
- 19
Rockport Colony in OctoberThis month
Highs average 55°13° and lows 32°0°, with 1 in26 mm of precipitation in a typical October.
- Record high
- 81°27° (2015)
- Record low
- −3°−19° (2020)
- Heating degree days
- 668
- Cooling degree days
- 2
Rockport Colony in November
Highs average 43°6° and lows 23°−5°, with 0.49 in12 mm of precipitation in a typical November.
- Record high
- 72°22° (2016)
- Record low
- −12°−24° (2014)
- Heating degree days
- 958
- Cooling degree days
- 0
Rockport Colony in December
Highs average 35°1° and lows 16°−9°, with 0.44 in11 mm of precipitation in a typical December.
- Record high
- 65°18° (2021)
- Record low
- −27°−33° (2022)
- Heating degree days
- 1227
- Cooling degree days
- 0