Climate and monthly weather forecastSan Mateo, CA
Climate and monthly weather forecast
The climate of San Mateo
Welcoming one to the sunny Californian city, San Mateo's weather bears the characteristics of a Mediterranean climate, warm summer (Csb), according to the Köppen climate classification. Nestled in the high-tech enclave of Silicon Valley and overlooking the Pacific Ocean, this city carries a mild and moderately wet weather. An analysis of the climate data reveals a spectrum of weather throughout the year.Temperature in San Mateo varies mildly, reflecting the coastal location. High temperatures average from 56.8°F (13.8°C) in January to a comfortable 71.2°F (21.8°C) from July to September. Low temperatures fluctuate between 46.9°F (8.3°C) in January to 56.7°F (13.7°C) in September, a rather consistent range indicating relatively warm winters.
Rainfall patterns display a vividly distinct seasonal divide - complete dryness from June to August followed by a gradual increase reaching peak levels of 0.55" (14mm) in February. The number of rain days per month presents a similar trend, with the maximum occurring in March and minimum in June and July with only 0.4 and 0.3 days respectively.
Humidity levels, ranging from 70% to 76%, demonstrate relatively high, consistent levels throughout the year. Moreover, San Mateo receives an average of 6 to 11.8 hours of sunshine daily, peaking in July, indicating that the city enjoys plenty of sun year-round.
The best time to visit San Mateo
The pleasant climate of San Mateo renders it a year-round destination. However, considering numerous factors such as sunshine hours, rainfall, and temperature, the optimal window to explore the city is between June and September. The city virtually receives no rainfall and sees an average temperature high of about 70°F (21.1°C), making these months perfect for outdoor activities. Also, with approximately 14 to 14.7 hours of daylight, there is ample time to soak in the city's splendors.The worst time to visit San Mateo
Although San Mateo entertains relatively mild weather throughout the year, the period from December to February sees the least agreeable conditions. These months receive the highest rainfall levels, ranging from 0.35" (9mm) to 0.55" (14mm), accompanied by the lowest temperatures with average lows of 47.5°F (8.6°C) in December to 48.7°F (9.3°C) in April.Spring weather in San Mateo
San Mateo spring season, from March to May, graces the city with pleasant weather. Though March is the wettest month with 0.35" (9mm) of rainfall over 6.8 days, rain begins to diminish drastically moving into April and May. Average high temperatures range from 59.2°F (15.1°C) in March to 63.9°F (17.7°C) in May while low temperatures progress upward between 47.7°F (8.7°C) and 50.7°F (10.4°C). Ample daylight available, from 12 hours in March to 14.2 hours in May, renders spring idyllic for outings and exploration.Summer weather in San Mateo
Commonly referred to as the dry season, summer in San Mateo begins in June and extends until August. It witnesses a range of the highest temperatures throughout the year, averaging between 68.5°F (20.3°C) and 71.2°F (21.8°C). An impressive record of no rain and elongated daylight hours reaching up to 14.7 hours in June along with low humidity level, sets the season as an ideal opportunity for a variety of outdoor activities under clear blue skies.Autumn weather in San Mateo
Autumn, covering months from September to November, offers mild conditions in San Mateo. Temperatures start to recede from 71.2°F (21.8°C) in September to 61.3°F (16.3°C) in November during daytime, and a drop from 56.7°F (13.7°C) to 50.9°F (10.5°C) is observed at night. Although the occurrence of rain starts to reappear, it still remains relatively low — 0.24" (6mm) over 2.7 days in November. The average daylight hours also decrease gradually, but still, abundant sunshine defines these months.Winter weather in San Mateo
San Mateo experiences a relatively milder winter compared to many places, with the coldest temperatures occurring from December to February. The high temperatures range from 55.8°F (13.2°C) to 57.7°F (14.3°C) and lows stretch from 46.9°F (8.3°C) to 48.7°F (9.3°C). Rainfall becomes more frequent during this period with December and February witnessing a maximum of around 0.35" (9mm) across a span of 5.5 days. Yet, despite the cooler temperatures and more frequent rainfall, San Mateo continues to enjoy a considerable amount of daylight, ranging from around 9.6 to 10.8 hours a day.Weather in January
January in San Mateo, California, USA, kicks off with typical winter conditions. The colder temperatures continue from the previous final month of last year, with the highest temperatures just slightly above average for this season, reaching a peak of 56.8°F (13.8°C). Weather in January »Weather in February
February in San Mateo remains relatively cool with an average minimum temperature of 47.1°F (8.4°C), coupled with slightly higher humidity levels. Residents and visitors should be prepared for potential rainfall, as this month records up to 0.55" (14mm) of rainfall. Weather in February »Weather in March
The weather in March brings warm temperatures hinting at the imminent arrival of Spring. March boasts an incremental jump in maximum temperatures, measuring at 59.2°F (15.1°C), an improvement over February. Alongside the temperature increase, this month also experiences an uptick in humidity, which can lead to some extra moisture in the air. Weather in March »Weather in April
As the year progresses into April, San Mateo earns its reputation for pleasant and moderate weather. Marking the true commencement of spring, there's a notable rise in maximum temperatures, bringing a high of 62.2°F (16.8°C). This month is punctuated by more time basking under the sun, with a significant reduction in cloud cover. Weather in April »Weather in May
May in San Mateo is a joy for those who favor mild and warm climates. There's a remarkable difference in temperature, in comparison to April. A worthwhile mention is that wind gusts continue to decrease, falling to 11mph (17.7km/h). The amount of sunshine and daylight continues to rise, gracifying every day with extended hours of daily light. Weather in May »Weather in June
June in San Mateo, California, sees a marked shift towards summer. The superb weather during June is characterized by average highs reaching a comfortable 68.5°F (20.3°C). Coupled with the pleasant temperatures, residents experience the most daylight of the year, optimizing their time in the outdoors. Weather in June »Weather in July
July is peak summer in San Mateo, bringing together several essential factors contributing to delightful weather. Having some of the best weather conditions, the month enjoys the highest temperature of 70.9°F (21.6°C). A unique feature of July is its very low number of rainy days, enhancing its appeal as a perfect month for beach visits and extended outdoor excursions. Weather in July »Weather in August
August weather in San Mateo stays in line with the warm and dry pattern established in July. Despite minimal changes in temperature from the previous month, the peak temperature this month records 71.2°F (21.8°C). As one of the driest months of the year, August is sterling for residents and tourists enthusiastic for open-air activities. Weather in August »Weather in September
Come September, San Mateo begins transitioning into autumn, yet maintaining the warmth characteristic of the summer months. September stands out as having one of the highest maximum monthly temperatures, equal to August, resting at 71.2°F (21.8°C). Weather in September »Weather in October
October in San Mateo brings the essence of autumn with a slight drop in temperature. October's weather is delightfully moderate and a stark departure from the persistent warmth experienced in September. The focus in October shifts toward increasing amounts of rainfall, where rainfall mounts to 0.04" (1mm) much from nothing in the previous month. Weather in October »Weather in November
November's weather in San Mateo, tends to get cooler, mirroring the transition phase leading up to winter. With temperatures comfortably cooler in comparison to October, November experiences a noticeable decrease in temperature. Weather in November »Weather in December
December in San Mateo ushers in the winter season, concluding the calendar year with the coolest temperatures. Compared to November, December witnesses a marginal drop in average temperatures, recording a low of 47.5°F (8.6°C). Weather in December »Updated: Aug 8, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Throughout the year, there are 32.6 rainfall days, and 2.13" (54mm) of precipitation is accumulated.
February is the month with the most rainfall. Rain falls for 3.2 days and accumulates 0.55" (14mm) of precipitation.
The months with the lowest UV index are February and December, with an average maximum UV index of 3.
The months with the highest humidity are March and August, with an average relative humidity of 76%.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.
In San Mateo, rain does not fall in June through August.
June has the longest days of the year, with an average of 14h and 42min of daylight.
June through September, with an average maximum UV index of 5, are months with the highest UV index in San Mateo.
July has the most sunshine of the year, with an average of 12h of sunshine.
August and September are identified as the warmest months, with an average high-temperature of 71.2°F (21.8°C).
January through May, September through December are months with rainfall.
October and November, with an average relative humidity of 70%, are the least humid months.
December, noted for its average high-temperature of 55.8°F (13.2°C) and an average low-temperature of 47.5°F (8.6°C), is considered the coldest month.
December has the shortest days of the year, with an average of 9h and 36min of daylight.
December has the least sunshine of the year, with an average of 5.9h of sunshine.
Average temperature
San Mateo, CA
The warmest months (with the highest average high temperature) are August and September (71.2°F).
The month with the lowest average high temperature is December (55.8°F).
The month with the highest average low temperature is September (56.7°F).
The coldest month (with the lowest average low temperature) is January (46.9°F).
Average pressure
San Mateo, CA
- Average pressure in January:
30.13"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
30.04"Hg - Average pressure in May:
29.98"Hg - Average pressure in June:
29.93"Hg
- Average pressure in July:
29.93"Hg - Average pressure in August:
29.93"Hg - Average pressure in September:
29.92"Hg - Average pressure in October:
29.99"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed
San Mateo, CA
- Average wind speed in January:
6.2mph - Average wind speed in February:
7.4mph - Average wind speed in March:
7.7mph - Average wind speed in April:
8mph - Average wind speed in May:
7.8mph - Average wind speed in June:
7.2mph
- Average wind speed in July:
6mph - Average wind speed in August:
5.9mph - Average wind speed in September:
5.9mph - Average wind speed in October:
5.9mph - Average wind speed in November:
6mph - Average wind speed in December:
6.9mph
The windiest month (with the highest average wind speed) is April (8mph).
The calmest months (with the lowest average wind speed) are August, September and October (5.9mph).
Average humidity
San Mateo, CA
The months with the highest relative humidity are March and August (76%).
The months with the lowest relative humidity are October and November (70%).
Average rainfall
San Mateo, CA
- Average rainfall in January:
0.31" - Average rainfall in February:
0.55" - Average rainfall in March:
0.35" - Average rainfall in April:
0.08" - Average rainfall in May:
0.16" - Average rainfall in June:
0"
The wettest month (with the highest rainfall) is February (0.55").
The driest months (with the least rainfall) are June, July and August (0").
Average rainfall days
San Mateo, CA
- Average rainfall days in January:
4.4 days - Average rainfall days in February:
3.2 days - Average rainfall days in March:
6.8 days - Average rainfall days in April:
3.8 days - Average rainfall days in May:
2.5 days - Average rainfall days in June:
0.4 days
- Average rainfall days in July:
0.3 days - Average rainfall days in August:
0.7 days - Average rainfall days in September:
0.9 days - Average rainfall days in October:
1.4 days - Average rainfall days in November:
2.7 days - Average rainfall days in December:
5.5 days
The month with the highest number of rainy days is March (6.8 days).
The month with the least rainy days is July (0.3 days).
Average daylight / Average sunshine
San Mateo, CA
- Average daylight in January:
9h and 54min - Average daylight in February:
10h and 48min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 12min - Average daylight in May:
14h and 12min - Average daylight in June:
14h and 42min
- Average daylight in July:
14h and 30min - Average daylight in August:
13h and 36min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 12min - Average daylight in November:
10h and 12min - Average daylight in December:
9h and 36min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in January:
6h and 12min - Average sunshine in February:
6h and 18min - Average sunshine in March:
7h and 54min - Average sunshine in April:
10h and 18min - Average sunshine in May:
10h and 42min - Average sunshine in June:
11h and 36min
- Average sunshine in July:
12h and 0min - Average sunshine in August:
11h and 48min - Average sunshine in September:
11h and 0min - Average sunshine in October:
7h and 6min - Average sunshine in November:
6h and 36min - Average sunshine in December:
5h and 54min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days
San Mateo, CA
- Average sunshine days in January:
25 days - Average sunshine days in February:
23.3 days - Average sunshine days in March:
23.8 days - Average sunshine days in April:
25.4 days - Average sunshine days in May:
27.6 days - Average sunshine days in June:
29.3 days
- Average sunshine days in July:
30.4 days - Average sunshine days in August:
30.2 days - Average sunshine days in September:
28.7 days - Average sunshine days in October:
28.8 days - Average sunshine days in November:
26.3 days - Average sunshine days in December:
24.4 days
The month with the most sunshine days is July (30.4 days).
The month with the least sunshine days is February (23.3 days).
Average UV index
San Mateo, CA
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February and December (UV index 3).
Average cloud cover
San Mateo, CA
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 11).
Average visibility
San Mateo, CA
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
