Swan Valley weather by month
What a typical year looks like in Swan Valley, Idaho: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Swan Valley, 4 km from Swan Valley; records cover 1960–2026.
The year at a glance
- Precipitation a year
- 20.1 in510 mm
- Snow a year
- Rare
- Last spring freeze
- Jun 18
- First fall freeze
- Sep 7
- Heating degree days
- 8,296
- Cooling degree days
- 152
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −9°−23° (heating, 99%) and 94°34° (cooling, 1%).
Month by month
Swan Valley in January
Highs average 30°−1° and lows 11°−12°, with 1.9 in47 mm of precipitation in a typical January.
- Record high
- 55°13° (1974)
- Record low
- −43°−42° (1963)
- Heating degree days
- 1373
- Cooling degree days
- 0
Swan Valley in February
Highs average 35°2° and lows 14°−10°, with 1.3 in34 mm of precipitation in a typical February.
- Record high
- 60°16° (1963)
- Record low
- −36°−38° (1982)
- Heating degree days
- 1141
- Cooling degree days
- 0
Swan Valley in March
Highs average 45°7° and lows 22°−6°, with 1.5 in39 mm of precipitation in a typical March.
- Record high
- 81°27° (2026)
- Record low
- −25°−32° (1971)
- Heating degree days
- 984
- Cooling degree days
- 0
Swan Valley in April
Highs average 56°13° and lows 27°−3°, with 1.9 in48 mm of precipitation in a typical April.
- Record high
- 83°28° (1992)
- Record low
- −3°−19° (1975)
- Heating degree days
- 700
- Cooling degree days
- 0
Swan Valley in May
Highs average 66°19° and lows 35°1°, with 2.5 in64 mm of precipitation in a typical May.
- Record high
- 91°33° (2003)
- Record low
- 12°−11° (1990)
- Heating degree days
- 458
- Cooling degree days
- 1
Swan Valley in June
Highs average 75°24° and lows 41°5°, with 2.1 in53 mm of precipitation in a typical June.
- Record high
- 101°38° (1988)
- Record low
- 20°−7° (1979)
- Heating degree days
- 229
- Cooling degree days
- 13
Swan Valley in July
Highs average 85°29° and lows 46°8°, with 1.3 in32 mm of precipitation in a typical July.
- Record high
- 104°40° (2026)
- Record low
- 26°−3° (1981)
- Heating degree days
- 65
- Cooling degree days
- 76
Swan Valley in August
Highs average 84°29° and lows 44°7°, with 1.3 in32 mm of precipitation in a typical August.
- Record high
- 102°39° (2025)
- Record low
- 23°−5° (1962)
- Heating degree days
- 80
- Cooling degree days
- 55
Swan Valley in September
Highs average 75°24° and lows 37°3°, with 1.6 in39 mm of precipitation in a typical September.
- Record high
- 103°39° (2022)
- Record low
- 8°−13° (1983)
- Heating degree days
- 279
- Cooling degree days
- 7
Swan Valley in OctoberThis month
Highs average 59°15° and lows 29°−2°, with 1.8 in46 mm of precipitation in a typical October.
- Record high
- 89°32° (2024)
- Record low
- −5°−21° (2019)
- Heating degree days
- 654
- Cooling degree days
- 0
Swan Valley in November
Highs average 43°6° and lows 20°−6°, with 1.6 in40 mm of precipitation in a typical November.
- Record high
- 72°22° (2020)
- Record low
- −21°−29° (1975)
- Heating degree days
- 1000
- Cooling degree days
- 0
Swan Valley in December
Highs average 32°0° and lows 12°−11°, with 1.4 in37 mm of precipitation in a typical December.
- Record high
- 58°14° (1979)
- Record low
- −43°−42° (1990)
- Heating degree days
- 1333
- Cooling degree days
- 0