Weather in Sonoma County

Calculated from weather data of Gnoss Field (KDVO) between 2020 and 2024.

Maximum temperatures (°C)

Month	Average	2024	2023	2022	2021	2020
January	14.8	15.5	14.5	15.6	15.6	14.9
February	16.8	15.9	14.8	18.8	18.3	20.1
March	17.8	17.3	14.5	20.5	18.5	17.5
April	21.0	21.1	20.3	20.8	22.3	21.1
May	23.5		21.3	25.1	25.5	25.1
June	27.7		24.1	28.8	27.6	29.3
July	29.9		30.5	28.6	30.3	30.1
August	30.5		31.6	31.0	30.8	32.2
September	29.5		26.6	31.1	30.3	31.5
October	26.1		26.3	25.5	23.5	29.1
November	19.1		20.0	17.6	18.6	19.3
December	14.6		15.9	12.1	12.5	15.8
Average	22.0	17.4	21.7	23.3	22.8	23.8

Average highest temperature per day

The maximum temperature is typically observed some hours after noon.

Minimum temperatures (°C)

Month	Average	2024	2023	2022	2021	2020
January	5.7	8	6	5	4	6
February	5.1	7	4	4	5	4
March	6.5	8	6	7	4	6
April	7.9	8	8	8	5	8
May	9.7		10	9	9	10
June	11.0		11	12	11	11
July	10.8		11	12	11	11
August	12.0		12	12	12	13
September	11.1		11	11	11	12
October	8.4		8	9	9	9
November	5.1		6	2	8	4
December	4.6		7	3	6	3
Average	8.1	7.5	8.3	7.8	7.9	7.9

Average lowest temperature per day

The minimum temperature is typically observed just before sunrise.

Cold and hot days

Number of days	2024	2023	2022	2021	2020
30 °C or warmer	0	54	61	58	91
25 °C or warmer	6	113	135	139	158
20 °C or warmer	24	181	218	208	218
0 °C or colder	0	7	11	3	9

Precipitation (%)

Month	Average	2024	2023	2022	2021	2020
January	8.0	15	13	1	3	2
February	6.1	22	6	0	0	0
March	4.3	11	9	1	2	2
April	1.8	4	0	1	0	2
May	0.6		0	0	0	1
June	0.0		0	0	0	0
July	0.2		0	0	0	0
August	0.2		0	0	0	1
September	0.2		0	1	0	0
October	0.6		0	0	4	0
November	1.6		3	1	1	1
December	5.6		16	5	4	1
Average	3.2	12.5	3.6	0.7	1.0	0.8

Precipitation during daylight period

Percentage of observations with observed rain, drizzle, snow or hail. Only observations between sunrise and sunset are taken into account.

Wind speed (km/h)

Month	Average	2024	2023	2022	2021	2020
January	9.2	10	11	7	9	9
February	11.1	10	11	9	12	9
March	11.4	13	14	10	12	10
April	11.5	11	13	14	12	11
May	12.7		11	16	15	11
June	11.4		11	12	13	12
July	9.8		10	10	9	10
August	9.4		9	9	9	10
September	10.1		11	10	10	9
October	8.7		8	8	11	7
November	7.7		8	8	7	9
December	8.8		9	8	11	8
Average	10.3	11.1	10.4	10.3	10.8	9.8

Average wind speed

Excluding wind gusts. Only observations between sunrise and sunset are taken into account.

Prevailing wind direction

Month	2024	2023	2022	2021	2020
January	S	S	SE	NE	W
February	S	W	NW	NW	N
March	W	SW	NW	W	W
April	W	W	W	SW	W
May		SW	W	W	SW
June		SW	W	W	W
July		S	SW	NE	NW
August		SW	W	N	W
September		SW	SW	NW	NW
October		W	NW	SW	SE
November		S	SW	SE	W
December		S	S	SW	SE

Prevailing wind direction

Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.

Sonoma County weather Q&A

What is the warmest month in Sonoma County?

The warmest month is August with an average temperature of 31 °C over the past years.

What is the coldest month in Sonoma County?

The coldest month is December with an average daytime temperature of 15 °C in the past few years.

Which month is the wettest in Sonoma County?

Chance of precipitation is the highest in January with a probability of around 8.0 %.

Which month is the driest in Sonoma County?

The least rainfall and snow can be expected in June. The probability is about 0.1 %.