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Contents
- The climate of Sunnyvale
- The best time to visit Sunnyvale
- The worst time to visit Sunnyvale
- Spring weather in Sunnyvale
- Summer weather in Sunnyvale
- Autumn weather in Sunnyvale
- Winter weather in Sunnyvale
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
The perfect blue sky, trees, buildings, and cute water fountain all reflected in the calm pool of water with birds in Sunnyvale, California
The climate of Sunnyvale
Sunnyvale, California is categorized under the Csb predominate climate according the Köppen climate classification, signifying a Mediterranean climate with warm summers. Geographically, Sunnyvale is located on the west coast of the United States. With an array of climatological parameters taken into account, the city's weather can show significant variations throughout the year.
A cursory examination of the climatological data illustrates a pattern of varying humidity percentages. From a low of 63% during September and October to a high of 73% in the month of March. The rainfall ranges from no rainfall in July to a maximum of 0.75" (19mm) in February and March. The amount of sunshine hours varies from 5.9 hours in December to a peak of 12.1 hours in July.
An interesting pattern is the lack of rainfall during the summer months, with almost negligible rainfall from June to August, making it an ideal location for those who enjoy dry, warm weather. Moreover, the city experiences mild winters, with the lowest recorded temperatures hovering around 44.6°F (7°C) in January, and reaching up to 56.8°F (13.8°C) in August.
A cursory examination of the climatological data illustrates a pattern of varying humidity percentages. From a low of 63% during September and October to a high of 73% in the month of March. The rainfall ranges from no rainfall in July to a maximum of 0.75" (19mm) in February and March. The amount of sunshine hours varies from 5.9 hours in December to a peak of 12.1 hours in July.
An interesting pattern is the lack of rainfall during the summer months, with almost negligible rainfall from June to August, making it an ideal location for those who enjoy dry, warm weather. Moreover, the city experiences mild winters, with the lowest recorded temperatures hovering around 44.6°F (7°C) in January, and reaching up to 56.8°F (13.8°C) in August.
The best time to visit Sunnyvale
The most agreeable time to relish the warm Mediterranean climate of Sunnyvale would be during late spring through early fall. Specifically, the period from May to October offers comfortable temperatures, ranging from daily highs of 65.8°F (18.8°C) to 76.5°F (24.7°C). The months from June to August are accompanied by minimal rainfall, amounting to just 0.04" (1mm) per month on average. These months also promise long daylight hours, stretching from 14.2 hours to 14.7 hours a day, and copious sunshine time averaging from 10.9 hours to 12 hours a day, providing more than enough daylight for outdoor activities and sightseeing.
The worst time to visit Sunnyvale
The months of January and February can be less favorable for visiting Sunnyvale, given the slightly cooler temperatures, relatively higher humidity, and increased precipitation. During this period, average low temperatures can drop to 44.2°F (6.8°C) to 44.6°F (7°C), and the city receives an average of 0.55" (14mm) and 0.75" (19mm) of rainfall respectively. However, it is worth noting that these figures are not severe, and if milder, moister conditions are preferable to a traveler, this time may still be suitable.
Spring weather in Sunnyvale
As spring unfolds in Sunnyvale from March to May, the climate begins to warm up progressively. Temperatures during this period are pleasant, with highs ranging from 62.2°F (16.8°C) in March to 69.4°F (20.8°C) in May. Simultaneously, the humidity levels drop consistently from 73% to 68%. The amount of sunlight increases significantly with each progressing month, offering between 7.9 hours to 10.9 hours daily. March exhibits a rainfall of 0.75" (19mm), which decreases to 0.24" (6mm) by April and further to just 0.2" (5mm) in May.
Summer weather in Sunnyvale
With the arrival of June, Sunnyvale experiences a Mediterranean summer, with temperature highs ranging from 76.5°F (24.7°C) in June to 79.9°F (26.6°C) in July and slightly dropping to 79.3°F (26.3°C) in August. Additionally, these months see the least amount of rainfall, averaging close to zero inches throughout the summer. The city basks in maximum sunlight during these months, with the number of sunshine hours rising steadily from 11.8 hours to 12.1 hours, before dipping to 12 hours in August.
Autumn weather in Sunnyvale
Autumn in Sunnyvale presents a gentle decline in temperatures, with highs measuring from 77.9°F (25.5°C) in September to 63.7°F (17.6°C) in November. The precipitation levels increase steadily in this period from 0.08" (2mm) in September to 0.43" (11mm) by November. In terms of sunshine, there is a gradual reduction from 11.1 hours in September to 6.6 hours by the end of November.
Winter weather in Sunnyvale
Winter in Sunnyvale is mild when compared to many other regions. From December to February, the temperature varies from lows of 44.2°F (6.8°C) to highs of 59.7°F (15.4°C). Rainfall levels are at their peak during these months, especially in February, measuring 0.71" (18mm). The amount of daily sunshine drops to 5.9 hours in December and recovers slightly to 6.4 hours in February. Despite the season, temperatures remain comfortable and the rainfall is not extreme.
Weather in January
January in Sunnyvale, California, is characterized by a mild Winter with average high temperatures hovering around 58.3°F (14.6°C) and slightly cooler nights at around 44.6°F (7°C). The relative humidity measures at 72%, ensuring a bit of a nip in the air, particularly during early morning and nights. Weather in January »
Weather in February
As Sunnyvale transitions from January to February, there's not much difference in temperature, but rainfall increases noticeably, with an average measurement of 0.75" (19mm) throughout the month. The hours of daylight extend to nearly 11, providing an opportunity to make the most of the day. Weather in February »
Weather in March
March heralds the arrival of Spring in Sunnyvale, with a substantial increase in daylight hours to 12 and a consequent increase in average sunshine hours. Despite the increased daylight, the temperatures remain relatively stable, indicating a gradual transition from Winter to Spring. Weather in March »
Weather in April
In April, Sunnyvale experiences a Meteorological Spring with a noticeable rise in the average high temperatures, reaching 65.8°F (18.8°C). The rainfall significantly decreases to an average of 0.24" (6mm), making way for more extended clear sky periods. Weather in April »
Weather in May
May witnesses a significant leap in the average high temperature, marking the onset of warmer weather conditions in Sunnyvale. The rainfall drops drastically to an average of 0.2" (5mm), with only three rainy days throughout the month. Weather in May »
Weather in June
June in Sunnyvale ushers in the summer season with the highest amount of daily sunshine, averaging 11.8 hours. Compared to May, the high temperature further increases to 76.5°F (24.7°C), promising bright beach days. However, rainfall gets rare, with nearly negligible precipitation seen this month. Weather in June »
Weather in July
July exhibits the height of summer in Sunnyvale with the highest average high temperature of the year at 79.9°F (26.6°C). Interestingly, despite the negligible rainfall seen in July, the relative humidity remains steady. As the sunshine hours maintain near their peak, wind speed sees a decline, just under 5mph (8km/h), indicating tranquil, sunny days. Weather in July »
Weather in August
August in Sunnyvale witnesses a slight decrease in average high temperature, accompanied by a virtually identical level of rainfall and humidity as July. Despite the brilliance of the summer sun, the maximum measured wind speed drops to 5.3mph (8.5km/h), indicating mellow breezy days. Weather in August »
Weather in September
September welcomes a steady decline in temperature, with the average high temperature falling to 77.9°F (25.5°C). Despite the drop in temperature, the average daylight hours remain appreciable at 12.4, and rainfall remains minimal. Weather in September »
Weather in October
October in Sunnyvale showcases the hearty autumn season with a notable reduction of the average high temperature to 71.8°F (22.1°C). While the rainfall sees a slight increase, it remains scattered and does not significantly alter the overall weather. Weather in October »
Weather in November
November brings cooler weather to Sunnyvale, with a substantial drop in average high temperature to 63.7°F (17.6°C). Rainfall increases to a significant average of 0.43" (11mm), and the number of rainy days doubles compared to October. Weather in November »
Weather in December
December, the final month of the year, witnesses a further dip in temperature, reaching an average high of 56.8°F (13.8°C). Noticing a steep increase in rainfall - up to an average of 0.71" (18mm) - December has the largest number of rainfall days, reaching 7.5. Weather in December »
Updated: Aug 15, 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
How many days does it rain?
In Sunnyvale, during the entire year, the rain falls for 50 days and collects up to 3.9" (99mm) of precipitation.
What is the rainiest month?
The wettest months are February and March, with an average 0.75" (19mm) of rainfall.
What is the month with the lowest UV index?
The months with the lowest UV index in Sunnyvale are February, November and December, with an average maximum UV index of 3.
What is the most humid month in Sunnyvale?
With an average relative humidity of 73%, March is the most humid month.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Sunnyvale, California, 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.
When are the longest days?
June has the longest days of the year, with an average of 14h and 42min of daylight.
When is the highest UV index?
June is the month with the highest UV index, with an average maximum UV index of 6.
What part of the year is the hottest?
July, marked by an average high-temperature of 79.9°F (26.6°C) and a low-temperature of 55.4°F (13°C), is the warmest month.
What is the driest month?
July is the only month when rain does not fall in Sunnyvale.
What month has the most sunshine?
The month with the most sunshine is July, with an average of 12.1h of sunshine.
When does it rain?
Months with rainfall are January through June, August through December.
What is the least humid month?
September and October, with an average relative humidity of 63%, are the least humid months.
What is the coldest month?
December is the month when Sunnyvale experiences its coldest temperatures, averaging a high of 56.8°F (13.8°C) and a low of 44.2°F (6.8°C).
What is the month with the shortest days in Sunnyvale?
The month with the shortest days is December, with an average of 9h and 36min of daylight.
What is the month with the least sunshine?
December has the least sunshine of the year, with an average of 5.9h of sunshine.
Average temperature
Sunnyvale, CA
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is December (56.8°F).
The month with the highest average low temperature is August (56.8°F).
The coldest months (with the lowest average low temperature) are February and December (44.2°F).
Average pressure
Sunnyvale, CA
- Average pressure in January:
30.13"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
30.04"Hg - Average pressure in May:
29.98"Hg - Average pressure in June:
29.92"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 months with the lowest atmospheric pressure are June and September (29.92"Hg).
Average wind speed
Sunnyvale, CA
- Average wind speed in January:
4.9mph - Average wind speed in February:
5.7mph - Average wind speed in March:
5.9mph - Average wind speed in April:
6.2mph - Average wind speed in May:
6.1mph - Average wind speed in June:
5.7mph
- Average wind speed in July:
4.8mph - Average wind speed in August:
4.7mph - Average wind speed in September:
4.6mph - Average wind speed in October:
4.7mph - Average wind speed in November:
4.7mph - Average wind speed in December:
5.3mph
The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest month (with the lowest average wind speed) is September (4.6mph).
Average humidity
Sunnyvale, CA
The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are September and October (63%).
Average rainfall
Sunnyvale, CA
- Average rainfall in January:
0.55" - Average rainfall in February:
0.75" - Average rainfall in March:
0.75" - Average rainfall in April:
0.24" - Average rainfall in May:
0.2" - Average rainfall in June:
0.04"
The wettest months (with the highest rainfall) are February and March (0.75").
The driest month (with the least rainfall) is July (0").
Average rainfall days
Sunnyvale, CA
- Average rainfall days in January:
6.3 days - Average rainfall days in February:
5.4 days - Average rainfall days in March:
9.6 days - Average rainfall days in April:
6.1 days - Average rainfall days in May:
3.1 days - Average rainfall days in June:
1.3 days
- Average rainfall days in July:
1.3 days - Average rainfall days in August:
0.4 days - Average rainfall days in September:
2.2 days - Average rainfall days in October:
2.4 days - Average rainfall days in November:
4.4 days - Average rainfall days in December:
7.5 days
The month with the highest number of rainy days is March (9.6 days).
The month with the least rainy days is August (0.4 days).
Average daylight / Average sunshine
Sunnyvale, CA
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 5min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 1min - Average daylight in May:
14h and 1min - Average daylight in June:
14h and 4min
- Average daylight in July:
14h and 2min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 1min - Average daylight in December:
9h and 4min
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 2min - Average sunshine in February:
6h and 2min - Average sunshine in March:
7h and 5min - Average sunshine in April:
10h and 3min - Average sunshine in May:
10h and 5min - Average sunshine in June:
11h and 5min
- Average sunshine in July:
12h and 1min - Average sunshine in August:
12h and 0min - Average sunshine in September:
11h and 1min - Average sunshine in October:
7h and 1min - Average sunshine in November:
6h and 4min - Average sunshine in December:
5h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days
Sunnyvale, CA
- Average sunshine days in January:
23.8 days - Average sunshine days in February:
21 days - Average sunshine days in March:
19.9 days - Average sunshine days in April:
23.1 days - Average sunshine days in May:
26.3 days - Average sunshine days in June:
28.1 days
- Average sunshine days in July:
29.8 days - Average sunshine days in August:
30.1 days - Average sunshine days in September:
27.5 days - Average sunshine days in October:
27.5 days - Average sunshine days in November:
24.1 days - Average sunshine days in December:
22.4 days
The month with the most sunshine days is August (30.1 days).
The month with the least sunshine days is March (19.9 days).
Average UV index
Sunnyvale, CA
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are February, November and December (UV index 3).
Average cloud cover
Sunnyvale, CA
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility
Sunnyvale, 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).
Sunnyvale, California, USA
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