Marietta-Alderwood weather by month
What a typical year looks like in Marietta-Alderwood, Washington: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Bellingham International Airport, 2 km from Marietta-Alderwood; records cover 1949–2026.
The year at a glance
- Precipitation a year
- 34.7 in882 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 7
- First fall freeze
- Oct 27
- Heating degree days
- 5,108
- Cooling degree days
- 75
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 19°−7° (heating, 99%) and 83°28° (cooling, 1%).
Month by month
Marietta-Alderwood in January
Highs average 46°8° and lows 34°1°, with 4.5 in114 mm of precipitation in a typical January.
- Record high
- 69°21° (2024)
- Record low
- −2°−19° (1950)
- Heating degree days
- 770
- Cooling degree days
- 0
Marietta-Alderwood in February
Highs average 49°9° and lows 35°1°, with 2.9 in72 mm of precipitation in a typical February.
- Record high
- 72°22° (2012)
- Record low
- −2°−19° (1950)
- Heating degree days
- 652
- Cooling degree days
- 0
Marietta-Alderwood in March
Highs average 53°12° and lows 38°3°, with 3.4 in85 mm of precipitation in a typical March.
- Record high
- 76°24° (2004)
- Record low
- 10°−12° (1951)
- Heating degree days
- 615
- Cooling degree days
- 0
Marietta-Alderwood in April
Highs average 58°14° and lows 42°5°, with 2.8 in70 mm of precipitation in a typical April.
- Record high
- 83°28° (2016)
- Record low
- 24°−4° (1951)
- Heating degree days
- 460
- Cooling degree days
- 0
Marietta-Alderwood in May
Highs average 64°18° and lows 47°8°, with 2.2 in57 mm of precipitation in a typical May.
- Record high
- 90°32° (1983)
- Record low
- 25°−4° (1954)
- Heating degree days
- 297
- Cooling degree days
- 1
Marietta-Alderwood in June
Highs average 68°20° and lows 52°11°, with 1.6 in41 mm of precipitation in a typical June.
- Record high
- 99°37° (2021)
- Record low
- 37°3° (1952)
- Heating degree days
- 164
- Cooling degree days
- 8
Marietta-Alderwood in July
Highs average 73°23° and lows 55°13°, with 0.88 in22 mm of precipitation in a typical July.
- Record high
- 96°36° (2009)
- Record low
- 40°4° (1952)
- Heating degree days
- 67
- Cooling degree days
- 31
Marietta-Alderwood in August
Highs average 73°23° and lows 55°13°, with 1.1 in29 mm of precipitation in a typical August.
- Record high
- 100°38° (2021)
- Record low
- 38°3° (1969)
- Heating degree days
- 65
- Cooling degree days
- 31
Marietta-Alderwood in September
Highs average 68°20° and lows 50°10°, with 2 in51 mm of precipitation in a typical September.
- Record high
- 89°32° (1951)
- Record low
- 28°−2° (1972)
- Heating degree days
- 189
- Cooling degree days
- 4
Marietta-Alderwood in OctoberThis month
Highs average 59°15° and lows 43°6°, with 3.9 in98 mm of precipitation in a typical October.
- Record high
- 80°27° (2022)
- Record low
- 20°−7° (1984)
- Heating degree days
- 432
- Cooling degree days
- 0
Marietta-Alderwood in November
Highs average 51°11° and lows 38°3°, with 5.2 in132 mm of precipitation in a typical November.
- Record high
- 73°23° (2016)
- Record low
- 3°−16° (1955)
- Heating degree days
- 616
- Cooling degree days
- 0
Marietta-Alderwood in December
Highs average 46°8° and lows 34°1°, with 4.3 in110 mm of precipitation in a typical December.
- Record high
- 67°19° (2014)
- Record low
- −1°−18° (1964)
- Heating degree days
- 781
- Cooling degree days
- 0