Rio Dell weather by month
What a typical year looks like in Rio Dell, California: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at SCOTIA, 2 km from Rio Dell; records cover 1926–2026.
The year at a glance
- Precipitation a year
- 47.7 in1211 mm
- Snow a year
- Rare
- Last spring freeze
- Feb 16
- First fall freeze
- Nov 29
- Heating degree days
- 3,487
- Cooling degree days
- 55
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 31°−1° (heating, 99%) and 85°29° (cooling, 1%).
Month by month
Rio Dell in January
Highs average 57°14° and lows 43°6°, with 8.6 in218 mm of precipitation in a typical January.
- Record high
- 76°24° (1940)
- Record low
- 20°−7° (1949)
- Heating degree days
- 477
- Cooling degree days
- 0
Rio Dell in February
Highs average 58°14° and lows 43°6°, with 7.8 in199 mm of precipitation in a typical February.
- Record high
- 82°28° (1930)
- Record low
- 23°−5° (1989)
- Heating degree days
- 413
- Cooling degree days
- 0
Rio Dell in March
Highs average 59°15° and lows 44°6°, with 6.9 in176 mm of precipitation in a typical March.
- Record high
- 86°30° (1929)
- Record low
- 29°−2° (1946)
- Heating degree days
- 423
- Cooling degree days
- 0
Rio Dell in April
Highs average 62°16° and lows 45°7°, with 3.9 in99 mm of precipitation in a typical April.
- Record high
- 92°33° (2014)
- Record low
- 31°−1° (2023)
- Heating degree days
- 349
- Cooling degree days
- 1
Rio Dell in May
Highs average 64°18° and lows 49°9°, with 1.9 in49 mm of precipitation in a typical May.
- Record high
- 97°36° (2008)
- Record low
- 33°1° (1950)
- Heating degree days
- 267
- Cooling degree days
- 3
Rio Dell in June
Highs average 67°20° and lows 51°11°, with 0.57 in14 mm of precipitation in a typical June.
- Record high
- 94°34° (1935)
- Record low
- 40°4° (1966)
- Heating degree days
- 175
- Cooling degree days
- 4
Rio Dell in July
Highs average 70°21° and lows 54°12°, with 0.14 in3.6 mm of precipitation in a typical July.
- Record high
- 93°34° (2024)
- Record low
- 40°4° (1991)
- Heating degree days
- 109
- Cooling degree days
- 8
Rio Dell in August
Highs average 72°22° and lows 54°12°, with 0.05 in1.3 mm of precipitation in a typical August.
- Record high
- 93°34° (2020)
- Record low
- 41°5° (1957)
- Heating degree days
- 78
- Cooling degree days
- 13
Rio Dell in September
Highs average 73°23° and lows 52°11°, with 0.47 in12 mm of precipitation in a typical September.
- Record high
- 104°40° (2017)
- Record low
- 37°3° (1950)
- Heating degree days
- 102
- Cooling degree days
- 18
Rio Dell in OctoberThis month
Highs average 69°20° and lows 48°9°, with 2.4 in60 mm of precipitation in a typical October.
- Record high
- 97°36° (1980)
- Record low
- 28°−2° (1971)
- Heating degree days
- 210
- Cooling degree days
- 8
Rio Dell in November
Highs average 61°16° and lows 45°7°, with 5.2 in133 mm of precipitation in a typical November.
- Record high
- 81°27° (1931)
- Record low
- 27°−3° (1978)
- Heating degree days
- 368
- Cooling degree days
- 0
Rio Dell in December
Highs average 55°13° and lows 42°5°, with 9.7 in246 mm of precipitation in a typical December.
- Record high
- 73°23° (1963)
- Record low
- 17°−8° (1932)
- Heating degree days
- 516
- Cooling degree days
- 0