Mount Vernon weather by month
What a typical year looks like in Mount Vernon, Oregon: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at John Day, 12 km from Mount Vernon; records cover 1903–2026.
The year at a glance
- Precipitation a year
- 12.3 in312 mm
- Snow a year
- 10 in24 cm
- Last spring freeze
- May 18
- First fall freeze
- Sep 22
- Heating degree days
- 6,867
- Cooling degree days
- 248
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 5°−15° (heating, 99%) and 99°37° (cooling, 1%).
Month by month
Mount Vernon in January
Highs average 40°5° and lows 21°−6°, with 1.1 in28 mm of precipitation and 4 in9 cm of snow in a typical January.
- Record high
- 69°21° (1904)
- Record low
- −24°−31° (1957)
- Heating degree days
- 1062
- Cooling degree days
- 0
Mount Vernon in February
Highs average 45°7° and lows 23°−5°, with 0.6 in15 mm of precipitation and 1.4 in3.6 cm of snow in a typical February.
- Record high
- 73°23° (1995)
- Record low
- −20°−29° (1985)
- Heating degree days
- 876
- Cooling degree days
- 0
Mount Vernon in March
Highs average 52°11° and lows 26°−3°, with 1.1 in29 mm of precipitation and 1.2 in3 cm of snow in a typical March.
- Record high
- 80°27° (1966)
- Record low
- −5°−21° (1906)
- Heating degree days
- 808
- Cooling degree days
- 0
Mount Vernon in April
Highs average 57°14° and lows 30°−1°, with 1.5 in38 mm of precipitation and 0.3 in0.8 cm of snow in a typical April.
- Record high
- 91°33° (1987)
- Record low
- 13°−11° (1966)
- Heating degree days
- 636
- Cooling degree days
- 0
Mount Vernon in May
Highs average 66°19° and lows 37°3°, with 1.8 in46 mm of precipitation in a typical May.
- Record high
- 98°37° (1983)
- Record low
- 13°−11° (1954)
- Heating degree days
- 414
- Cooling degree days
- 3
Mount Vernon in June
Highs average 75°24° and lows 43°6°, with 1.3 in33 mm of precipitation in a typical June.
- Record high
- 103°39° (1974)
- Record low
- 25°−4° (1966)
- Heating degree days
- 215
- Cooling degree days
- 23
Mount Vernon in July
Highs average 86°30° and lows 48°9°, with 0.43 in11 mm of precipitation in a typical July.
- Record high
- 110°43° (2002)
- Record low
- 35°2° (1962)
- Heating degree days
- 53
- Cooling degree days
- 114
Mount Vernon in August
Highs average 86°30° and lows 46°8°, with 0.5 in13 mm of precipitation in a typical August.
- Record high
- 112°44° (1961)
- Record low
- 30°−1° (1992)
- Heating degree days
- 61
- Cooling degree days
- 90
Mount Vernon in September
Highs average 77°25° and lows 39°4°, with 0.52 in13 mm of precipitation in a typical September.
- Record high
- 110°43° (1904)
- Record low
- 21°−6° (1965)
- Heating degree days
- 231
- Cooling degree days
- 18
Mount Vernon in OctoberThis month
Highs average 62°17° and lows 31°0°, with 1 in26 mm of precipitation and 0.2 in0.5 cm of snow in a typical October.
- Record high
- 95°35° (1980)
- Record low
- 4°−16° (2002)
- Heating degree days
- 569
- Cooling degree days
- 0
Mount Vernon in November
Highs average 48°9° and lows 26°−4°, with 1.2 in30 mm of precipitation and 1 in2.5 cm of snow in a typical November.
- Record high
- 79°26° (1988)
- Record low
- −9°−23° (1955)
- Heating degree days
- 854
- Cooling degree days
- 0
Mount Vernon in December
Highs average 39°4° and lows 21°−6°, with 1.1 in29 mm of precipitation and 2 in5.1 cm of snow in a typical December.
- Record high
- 66°19° (1980)
- Record low
- −23°−31° (1983)
- Heating degree days
- 1088
- Cooling degree days
- 0