Mount Vernon weather by month
What a typical year looks like in Mount Vernon, Washington: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at SEDRO-WOOLLEY, 11 km from Mount Vernon; records cover 1896–2026.
The year at a glance
- Precipitation a year
- 48.5 in1233 mm
- Snow a year
- 6 in14 cm
- Last spring freeze
- Mar 31
- First fall freeze
- Nov 3
- Heating degree days
- 5,069
- Cooling degree days
- 86
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 20°−7° (heating, 99%) and 85°29° (cooling, 1%).
Month by month
Mount Vernon in January
Highs average 46°8° and lows 35°2°, with 6.2 in157 mm of precipitation and 0.6 in1.5 cm of snow in a typical January.
- Record high
- 68°20° (2015)
- Record low
- −2°−19° (1957)
- Heating degree days
- 764
- Cooling degree days
- 0
Mount Vernon in February
Highs average 49°9° and lows 35°2°, with 4.1 in104 mm of precipitation and 0.2 in0.5 cm of snow in a typical February.
- Record high
- 74°23° (1986)
- Record low
- −1°−18° (1950)
- Heating degree days
- 648
- Cooling degree days
- 0
Mount Vernon in March
Highs average 53°12° and lows 38°3°, with 4.8 in121 mm of precipitation and 0.4 in1 cm of snow in a typical March.
- Record high
- 82°28° (1928)
- Record low
- 8°−13° (1955)
- Heating degree days
- 608
- Cooling degree days
- 0
Mount Vernon in April
Highs average 58°15° and lows 41°5°, with 4.2 in106 mm of precipitation in a typical April.
- Record high
- 94°34° (1910)
- Record low
- 25°−4° (1901)
- Heating degree days
- 456
- Cooling degree days
- 0
Mount Vernon in May
Highs average 65°18° and lows 47°8°, with 3.5 in88 mm of precipitation in a typical May.
- Record high
- 95°35° (1910)
- Record low
- 25°−4° (1906)
- Heating degree days
- 289
- Cooling degree days
- 2
Mount Vernon in June
Highs average 69°20° and lows 51°10°, with 2.6 in66 mm of precipitation in a typical June.
- Record high
- 99°37° (1915)
- Record low
- 30°−1° (1908)
- Heating degree days
- 168
- Cooling degree days
- 9
Mount Vernon in July
Highs average 75°24° and lows 53°12°, with 1.3 in34 mm of precipitation in a typical July.
- Record high
- 98°37° (2009)
- Record low
- 31°−1° (1901)
- Heating degree days
- 71
- Cooling degree days
- 34
Mount Vernon in August
Highs average 75°24° and lows 53°12°, with 1.6 in41 mm of precipitation in a typical August.
- Record high
- 97°36° (1960)
- Record low
- 34°1° (1909)
- Heating degree days
- 63
- Cooling degree days
- 34
Mount Vernon in September
Highs average 70°21° and lows 49°10°, with 2.9 in73 mm of precipitation in a typical September.
- Record high
- 91°33° (1944)
- Record low
- 28°−2° (1908)
- Heating degree days
- 175
- Cooling degree days
- 7
Mount Vernon in OctoberThis month
Highs average 60°15° and lows 43°6°, with 5 in126 mm of precipitation and 0.1 in0.3 cm of snow in a typical October.
- Record high
- 86°30° (1987)
- Record low
- 20°−7° (1935)
- Heating degree days
- 422
- Cooling degree days
- 0
Mount Vernon in November
Highs average 50°10° and lows 39°4°, with 7 in178 mm of precipitation and 0.7 in1.8 cm of snow in a typical November.
- Record high
- 76°24° (1908)
- Record low
- 3°−16° (1955)
- Heating degree days
- 615
- Cooling degree days
- 0
Mount Vernon in December
Highs average 45°7° and lows 34°1°, with 5.5 in138 mm of precipitation and 4 in9 cm of snow in a typical December.
- Record high
- 74°23° (1939)
- Record low
- 1°−17° (1968)
- Heating degree days
- 790
- Cooling degree days
- 0