Princeton weather by month
What a typical year looks like in Princeton, Idaho: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at MOSCOW U OF I, 23 km from Princeton; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 27.8 in706 mm
- Snow a year
- 51 in129 cm
- Last spring freeze
- May 19
- First fall freeze
- Sep 17
- Heating degree days
- 6,949
- Cooling degree days
- 196
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 4°−16° (heating, 99%) and 97°36° (cooling, 1%).
Month by month
Princeton in January
Highs average 37°3° and lows 22°−5°, with 3.3 in85 mm of precipitation and 15 in37 cm of snow in a typical January.
- Record high
- 58°14° (1971)
- Record low
- −26°−32° (1950)
- Heating degree days
- 1091
- Cooling degree days
- 0
Princeton in February
Highs average 42°6° and lows 24°−5°, with 2.6 in65 mm of precipitation and 9 in22 cm of snow in a typical February.
- Record high
- 66°19° (1995)
- Record low
- −26°−32° (1996)
- Heating degree days
- 899
- Cooling degree days
- 0
Princeton in March
Highs average 50°10° and lows 28°−2°, with 3.1 in77 mm of precipitation and 5 in12 cm of snow in a typical March.
- Record high
- 75°24° (2025)
- Record low
- −10°−23° (2019)
- Heating degree days
- 804
- Cooling degree days
- 0
Princeton in April
Highs average 58°14° and lows 32°0°, with 2.8 in70 mm of precipitation and 1 in2.5 cm of snow in a typical April.
- Record high
- 88°31° (1910)
- Record low
- 11°−12° (1936)
- Heating degree days
- 600
- Cooling degree days
- 0
Princeton in May
Highs average 67°20° and lows 38°3°, with 2.6 in66 mm of precipitation and 0.2 in0.5 cm of snow in a typical May.
- Record high
- 94°34° (1928)
- Record low
- 19°−7° (1954)
- Heating degree days
- 388
- Cooling degree days
- 3
Princeton in June
Highs average 73°23° and lows 42°6°, with 1.7 in44 mm of precipitation in a typical June.
- Record high
- 105°41° (2021)
- Record low
- 28°−2° (1973)
- Heating degree days
- 232
- Cooling degree days
- 13
Princeton in July
Highs average 84°29° and lows 45°7°, with 0.66 in17 mm of precipitation in a typical July.
- Record high
- 105°41° (1928)
- Record low
- 31°−1° (1999)
- Heating degree days
- 80
- Cooling degree days
- 75
Princeton in August
Highs average 86°30° and lows 45°7°, with 0.7 in18 mm of precipitation in a typical August.
- Record high
- 109°43° (1961)
- Record low
- 30°−1° (1935)
- Heating degree days
- 72
- Cooling degree days
- 84
Princeton in September
Highs average 76°25° and lows 40°4°, with 1 in26 mm of precipitation in a typical September.
- Record high
- 102°39° (2025)
- Record low
- 20°−7° (1934)
- Heating degree days
- 232
- Cooling degree days
- 21
Princeton in OctoberThis month
Highs average 61°16° and lows 33°0°, with 2.4 in61 mm of precipitation and 0.2 in0.5 cm of snow in a typical October.
- Record high
- 88°31° (1934)
- Record low
- 2°−17° (1935)
- Heating degree days
- 569
- Cooling degree days
- 0
Princeton in November
Highs average 45°7° and lows 27°−3°, with 3.5 in89 mm of precipitation and 6 in15 cm of snow in a typical November.
- Record high
- 73°23° (1999)
- Record low
- −14°−26° (1896)
- Heating degree days
- 866
- Cooling degree days
- 0
Princeton in December
Highs average 36°2° and lows 22°−6°, with 3.5 in88 mm of precipitation and 16 in39 cm of snow in a typical December.
- Record high
- 61°16° (2021)
- Record low
- −42°−41° (1968)
- Heating degree days
- 1116
- Cooling degree days
- 0