Weather in San Bernardino County

Calculated from weather data of Ontario International Airport (KONT) between 2020 and 2024.

Maximum temperatures (°F)

Month	Average	2024	2023	2022	2021	2020
January	67.0	65.0	60.0	68.0	69.0	69.0
February	67.0	63.0	63.0	72.0	69.0	72.0
March	70.0	66.0	62.0	75.0	69.0	66.0
April	77.0		75.0	77.0	78.0	73.0
May	78.0		73.0	80.0	80.0	85.0
June	87.0		78.0	91.0	92.0	87.0
July	95.0		95.0	92.0	96.0	93.0
August	95.0		94.0	96.0	95.0	97.0
September	90.0		83.0	93.0	91.0	97.0
October	84.0		85.0	81.0	82.0	88.0
November	76.0		76.0	69.0	80.0	76.0
December	67.0		70.0	61.0	62.0	70.0
Average	78.0	65.0	76.0	80.0	80.0	81.0

Average highest temperature per day

The maximum temperature is typically observed some hours after noon.

Minimum temperatures (°F)

Month	Average	2024	2023	2022	2021	2020
January	46.0	46	44	46	46	46
February	47.0	48	42	48	47	48
March	49.0	48	46	50	47	49
April	54.0		51	55	54	55
May	57.0		55	56	58	60
June	62.0		58	64	64	62
July	67.0		67	65	69	65
August	68.0		68	69	69	70
September	66.0		64	70	66	67
October	60.0		60	60	59	62
November	52.0		52	47	54	50
December	47.0		49	43	45	46
Average	55.0	47.0	55.0	57.0	56.0	57.0

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
86 °F or warmer	0	82	120	131	141
77 °F or warmer	2	162	200	206	211
68 °F or warmer	23	250	287	289	290
32 °F or colder	0	0	0	0	0

Precipitation (%)

Month	Average	2024	2023	2022	2021	2020
January	7.3	7	18	1	4	0
February	7.6	19	10	2	2	0
March	8.0	11	23	3	5	7
April	2.3		2	1	2	11
May	2.9		6	1	1	1
June	0.7		2	0	0	2
July	0.2		0	0	1	0
August	0.7		4	0	1	0
September	0.6		2	2	0	0
October	1.3		1	0	6	1
November	2.8		2	6	0	1
December	6.8		4	9	17	2
Average	4.2	12.1	6.2	1.7	3.2	2.1

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 (miles per hour)

Month	Average	2024	2023	2022	2021	2020
January	5.2	4	7	5	6	4
February	5.8	5	6	8	6	7
March	6.7	6	6	8	7	7
April	7.2		6	7	7	6
May	7.1		7	7	7	7
June	7.1		6	7	7	8
July	6.9		7	7	7	7
August	7.1		7	7	7	7
September	6.6		6	6	6	6
October	6.5		6	6	6	6
November	5.5		6	6	5	5
December	4.9		4	4	5	5
Average	6.3	5.1	6.2	6.5	6.4	6.4

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	W	N	NW	N	W
February	W	W	NW	W	N
March	W	SW	W	SW	SW
April		W	W	W	SW
May		SW	W	W	SW
June		SW	W	W	W
July		W	W	W	W
August		W	W	W	W
September		SW	W	W	W
October		W	SW	W	W
November		N	W	W	W
December		W	SW	W	NW

Prevailing wind direction

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

San Bernardino County weather Q&A

What is the warmest month in San Bernardino County?

The warmest month is July with an average temperature of 95 °F over the past years.

What is the coldest month in San Bernardino County?

The coldest month is January with an average daytime temperature of 67 °F in the past few years.

Which month is the wettest in San Bernardino County?

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

Which month is the driest in San Bernardino County?

The least rainfall and snow can be expected in July. The probability is about 0.3 %.