Union weather by month
What a typical year looks like in Union, Washington: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Cushman Powerhouse #2, 6 km from Union; records cover 1973–2026.
The year at a glance
- Precipitation a year
- 92 in2336 mm
- Snow a year
- 4 in11 cm
- Last spring freeze
- Apr 1
- First fall freeze
- Nov 10
- Heating degree days
- 5,109
- Cooling degree days
- 122
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 25°−4° (heating, 99%) and 88°31° (cooling, 1%).
Month by month
Union in January
Highs average 45°7° and lows 36°2°, with 15.5 in393 mm of precipitation and 1.3 in3.3 cm of snow in a typical January.
- Record high
- 60°16° (1978)
- Record low
- 11°−12° (1980)
- Heating degree days
- 760
- Cooling degree days
- 0
Union in February
Highs average 48°9° and lows 35°2°, with 9.2 in234 mm of precipitation and 1.2 in3 cm of snow in a typical February.
- Record high
- 71°22° (1986)
- Record low
- 14°−10° (1989)
- Heating degree days
- 655
- Cooling degree days
- 0
Union in March
Highs average 53°11° and lows 37°3°, with 9.9 in251 mm of precipitation and 0.1 in0.3 cm of snow in a typical March.
- Record high
- 77°25° (1979)
- Record low
- 21°−6° (1989)
- Heating degree days
- 625
- Cooling degree days
- 0
Union in April
Highs average 58°14° and lows 40°5°, with 6.1 in156 mm of precipitation in a typical April.
- Record high
- 83°28° (1998)
- Record low
- 28°−2° (1975)
- Heating degree days
- 483
- Cooling degree days
- 0
Union in May
Highs average 65°19° and lows 46°8°, with 3 in77 mm of precipitation in a typical May.
- Record high
- 92°33° (1983)
- Record low
- 31°−1° (1985)
- Heating degree days
- 296
- Cooling degree days
- 3
Union in June
Highs average 70°21° and lows 50°10°, with 1.9 in49 mm of precipitation in a typical June.
- Record high
- 105°41° (2021)
- Record low
- 34°1° (1976)
- Heating degree days
- 169
- Cooling degree days
- 14
Union in July
Highs average 76°24° and lows 54°12°, with 0.87 in22 mm of precipitation in a typical July.
- Record high
- 96°36° (2004)
- Record low
- 41°5° (1974)
- Heating degree days
- 58
- Cooling degree days
- 51
Union in August
Highs average 76°24° and lows 54°12°, with 1.4 in36 mm of precipitation in a typical August.
- Record high
- 97°36° (1981)
- Record low
- 39°4° (1973)
- Heating degree days
- 55
- Cooling degree days
- 47
Union in September
Highs average 69°21° and lows 50°10°, with 3 in77 mm of precipitation in a typical September.
- Record high
- 91°33° (1988)
- Record low
- 34°1° (1983)
- Heating degree days
- 170
- Cooling degree days
- 7
Union in OctoberThis month
Highs average 58°15° and lows 44°7°, with 9.1 in231 mm of precipitation in a typical October.
- Record high
- 82°28° (1980)
- Record low
- 26°−3° (2006)
- Heating degree days
- 428
- Cooling degree days
- 0
Union in November
Highs average 50°10° and lows 39°4°, with 15.7 in399 mm of precipitation and 0.1 in0.3 cm of snow in a typical November.
- Record high
- 68°20° (1980)
- Record low
- 13°−11° (1985)
- Heating degree days
- 626
- Cooling degree days
- 0
Union in December
Highs average 44°7° and lows 35°2°, with 16.2 in412 mm of precipitation and 1.7 in4.3 cm of snow in a typical December.
- Record high
- 66°19° (1980)
- Record low
- 11°−12° (1983)
- Heating degree days
- 784
- Cooling degree days
- 0