Climate and monthly weather forecastSunnyvale, CA

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.

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 »