August weather forecast
Sunnyvale, CA

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The perfect blue sky, trees, buildings, and cute water fountain all reflected in the calm pool of water with birds in Sunnyvale, California
The perfect blue sky, trees, buildings, and cute water fountain all reflected in the calm pool of water with birds in Sunnyvale, California

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. The UV index, pressure rating, and visibility remain stable, contributing to consistent weather conditions throughout the month. Even though August still carries the warmth of the peak summer, the month brings in a hint of incoming autumn.

Temperature

As July turns into August, the average high-temperatures rest at a still moderately hot 79.3°F (26.3°C), showing a minor variation from the prior month. Contrasting the daytime warmth, Sunnyvale's August nights cool down to an average of 56.8°F (13.8°C).

Humidity

In August, the average relative humidity is 66%.

Rainfall

January through June, August through December are months with rainfall. August is the first month it rains. Throughout August, in the average 0.4 rainfall days, it receives 0.04" (1mm) of precipitation. Throughout the year, there are 50 rainfall days, and 3.9" (99mm) of precipitation is accumulated.

Daylight

In August, the average length of the day is 13h and 33min.
On the first day of the month, sunrise is at 6:13 am and sunset at 8:15 pm. On the last day of August, sunrise is at 6:38 am and sunset at 7:37 pm PDT.

Sunshine

The average sunshine in August is 12h.

UV index

The average daily maximum UV index in August is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: In August, the average maximum UV index of 5 translates into the following recommendations:
Exercise prevention - Protecting skin and eyes from harm is required. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.

Frequently asked questions

What are August temperatures in Sunnyvale?

In August, in Sunnyvale, the average high-temperature is 79.3°F (26.3°C), and the average low-temperature is 56.8°F (13.8°C).

What is the average humidity in August?

In August, the average relative humidity is 66%.

When does it start raining?

August is the first month it rains. Throughout August, in the average 0.4 rainfall days, it receives 0.04" (1mm) of precipitation.

How many hours of daylight does Sunnyvale have in August?

In Sunnyvale, the average day length in August is 13h and 33min.

When is the sunrise / sunset in August?

In August, on the first day of the month, sunrise is at 6:13 am and sunset at 8:15 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 7:37 pm PDT.

How long on average sun shines in August?

In August, the average sunshine duration is 12h.

What is the UV index reading in August?

In Sunnyvale, the average daily maximum UV index in August is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Sunnyvale, CA

Average temperature in August - Sunnyvale, CA
  • Average high temperature in August: 79.3°F

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).

  • Average low temperature in August: 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 in August
Sunnyvale, CA

Average pressure in August - Sunnyvale, CA
  • Average pressure in August: 29.93"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 in August
Sunnyvale, CA

Average wind speed in August - Sunnyvale, CA
  • Average wind speed in August: 4.7mph

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 in August
Sunnyvale, CA

Average humidity in August - Sunnyvale, CA
  • Average humidity in August: 66%

The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are September and October (63%).

Average rainfall in August
Sunnyvale, CA

Average rainfall in August - Sunnyvale, CA
  • Average rainfall in August: 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 in August
Sunnyvale, CA

Average rainfall days in August - Sunnyvale, CA
  • Average rainfall days in August: 0.4 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 in August /
Average sunshine in August
Sunnyvale, CA

Average daylight in August / Average sunshine in August - Sunnyvale, CA
  • Average daylight in August: 13h 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 August: 12h and 0min

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 in August
Sunnyvale, CA

Average sunshine days in August - Sunnyvale, CA
  • Average sunshine days in August: 30.1 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 in August
Sunnyvale, CA

Average UV index in August - Sunnyvale, CA
  • Average UV index in August: 5

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 in August
Sunnyvale, CA

Average cloud cover in August - Sunnyvale, CA
  • Average cloud cover in August: 8

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 in August
Sunnyvale, CA

Average visibility in August - Sunnyvale, CA
  • Average visibility in August: 6mi

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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