Waterloo weather by month
What a typical year looks like in Waterloo, Oregon: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at FOSTER DAM, 15 km from Waterloo; records cover 1969–2026.
The year at a glance
- Precipitation a year
- 54.5 in1383 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 15
- First fall freeze
- Oct 28
- Heating degree days
- 4,811
- Cooling degree days
- 234
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 21°−6° (heating, 99%) and 96°36° (cooling, 1%).
Month by month
Waterloo in January
Highs average 48°9° and lows 34°1°, with 7.2 in182 mm of precipitation and 0.1 in0.3 cm of snow in a typical January.
- Record high
- 67°19° (1986)
- Record low
- 0°−18° (1979)
- Heating degree days
- 747
- Cooling degree days
- 0
Waterloo in February
Highs average 51°11° and lows 35°1°, with 5.6 in141 mm of precipitation in a typical February.
- Record high
- 71°22° (1992)
- Record low
- 2°−17° (1989)
- Heating degree days
- 620
- Cooling degree days
- 0
Waterloo in March
Highs average 56°13° and lows 37°3°, with 6.3 in159 mm of precipitation in a typical March.
- Record high
- 82°28° (2025)
- Record low
- 19°−7° (2019)
- Heating degree days
- 583
- Cooling degree days
- 0
Waterloo in April
Highs average 60°16° and lows 40°4°, with 5.4 in136 mm of precipitation in a typical April.
- Record high
- 90°32° (2023)
- Record low
- 22°−6° (2008)
- Heating degree days
- 452
- Cooling degree days
- 1
Waterloo in May
Highs average 67°19° and lows 44°7°, with 3.8 in97 mm of precipitation in a typical May.
- Record high
- 96°36° (1987)
- Record low
- 26°−3° (2013)
- Heating degree days
- 302
- Cooling degree days
- 6
Waterloo in June
Highs average 73°23° and lows 48°9°, with 2.5 in62 mm of precipitation in a typical June.
- Record high
- 112°44° (2021)
- Record low
- 35°2° (1984)
- Heating degree days
- 160
- Cooling degree days
- 22
Waterloo in July
Highs average 82°28° and lows 51°11°, with 0.54 in14 mm of precipitation in a typical July.
- Record high
- 106°41° (2009)
- Record low
- 39°4° (2008)
- Heating degree days
- 44
- Cooling degree days
- 86
Waterloo in August
Highs average 83°28° and lows 50°10°, with 0.64 in16 mm of precipitation in a typical August.
- Record high
- 105°41° (1981)
- Record low
- 36°2° (1973)
- Heating degree days
- 43
- Cooling degree days
- 88
Waterloo in September
Highs average 76°25° and lows 47°8°, with 2 in51 mm of precipitation in a typical September.
- Record high
- 102°39° (1987)
- Record low
- 31°−1° (2007)
- Heating degree days
- 132
- Cooling degree days
- 30
Waterloo in OctoberThis month
Highs average 64°18° and lows 42°5°, with 4.6 in118 mm of precipitation in a typical October.
- Record high
- 93°34° (1980)
- Record low
- 20°−7° (2002)
- Heating degree days
- 373
- Cooling degree days
- 1
Waterloo in November
Highs average 53°12° and lows 38°3°, with 7.6 in194 mm of precipitation in a typical November.
- Record high
- 75°24° (1975)
- Record low
- 16°−9° (1993)
- Heating degree days
- 592
- Cooling degree days
- 0
Waterloo in December
Highs average 47°8° and lows 34°1°, with 8.4 in213 mm of precipitation in a typical December.
- Record high
- 69°21° (1974)
- Record low
- 0°−18° (1972)
- Heating degree days
- 763
- Cooling degree days
- 0