Guerneville weather by month
What a typical year looks like in Guerneville, California: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Fort Ross, 22 km from Guerneville; records cover 1897–2026.
The year at a glance
- Precipitation a year
- 39.2 in995 mm
- Snow a year
- Rare
- Last spring freeze
- Mar 11
- First fall freeze
- Nov 23
- Heating degree days
- 4,180
- Cooling degree days
- 9
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 30°−1° (heating, 99%) and 81°27° (cooling, 1%).
Month by month
Guerneville in January
Highs average 57°14° and lows 42°5°, with 7.2 in182 mm of precipitation in a typical January.
- Record high
- 83°28° (1899)
- Record low
- 22°−6° (1987)
- Heating degree days
- 490
- Cooling degree days
- 0
Guerneville in February
Highs average 59°15° and lows 42°6°, with 7 in177 mm of precipitation in a typical February.
- Record high
- 79°26° (1987)
- Record low
- 20°−7° (2020)
- Heating degree days
- 410
- Cooling degree days
- 0
Guerneville in March
Highs average 59°15° and lows 42°6°, with 5.2 in131 mm of precipitation in a typical March.
- Record high
- 78°26° (1953)
- Record low
- 21°−6° (2020)
- Heating degree days
- 453
- Cooling degree days
- 0
Guerneville in April
Highs average 60°16° and lows 43°6°, with 2.9 in73 mm of precipitation in a typical April.
- Record high
- 86°30° (2000)
- Record low
- 26°−3° (1994)
- Heating degree days
- 405
- Cooling degree days
- 0
Guerneville in May
Highs average 62°17° and lows 45°7°, with 1.6 in41 mm of precipitation in a typical May.
- Record high
- 85°29° (1997)
- Record low
- 26°−3° (2020)
- Heating degree days
- 357
- Cooling degree days
- 0
Guerneville in June
Highs average 66°19° and lows 46°8°, with 0.48 in12 mm of precipitation in a typical June.
- Record high
- 89°32° (2019)
- Record low
- 31°−1° (2020)
- Heating degree days
- 266
- Cooling degree days
- 0
Guerneville in July
Highs average 66°19° and lows 48°9°, with 0.04 in1 mm of precipitation in a typical July.
- Record high
- 88°31° (1898)
- Record low
- 35°2° (1991)
- Heating degree days
- 251
- Cooling degree days
- 1
Guerneville in August
Highs average 67°19° and lows 50°10°, with 0.07 in1.8 mm of precipitation in a typical August.
- Record high
- 92°33° (2017)
- Record low
- 29°−2° (2020)
- Heating degree days
- 214
- Cooling degree days
- 1
Guerneville in September
Highs average 67°20° and lows 48°9°, with 0.17 in4.3 mm of precipitation in a typical September.
- Record high
- 97°36° (1950)
- Record low
- 0°−18° (2012)
- Heating degree days
- 218
- Cooling degree days
- 2
Guerneville in OctoberThis month
Highs average 66°19° and lows 47°8°, with 2 in50 mm of precipitation in a typical October.
- Record high
- 93°34° (2003)
- Record low
- 25°−4° (2020)
- Heating degree days
- 259
- Cooling degree days
- 4
Guerneville in November
Highs average 61°16° and lows 44°7°, with 4.2 in108 mm of precipitation in a typical November.
- Record high
- 88°31° (2019)
- Record low
- 24°−4° (2019)
- Heating degree days
- 373
- Cooling degree days
- 1
Guerneville in December
Highs average 57°14° and lows 42°5°, with 8.4 in214 mm of precipitation in a typical December.
- Record high
- 76°24° (1958)
- Record low
- 20°−7° (1972)
- Heating degree days
- 484
- Cooling degree days
- 0