August weather forecast
Foster City, CA

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Weather in August

August, the last month of the summer in Foster City, is also an agreeable month, with temperature in the range of an average low of 56.3°F (13.5°C) and an average high of 71.2°F (21.8°C).

Temperature

Foster City's warmest months, August and September, record an average high-temperature of 71.2°F (21.8°C).

Humidity

The months with the highest humidity in Foster City are March and August, with an average relative humidity of 76%.

Rainfall

June through August are months without rainfall in Foster City.

Daylight

The average length of the day in August in Foster City, California, is 13h and 34min.
On the first day of the month, sunrise is at 6:13 am and sunset at 8:16 pm. On the last day of August, sunrise is at 6:39 am and sunset at 7:39 pm PDT.

Sunshine

In Foster City, the average sunshine in August is 11.8h.

UV index

June through September, with an average maximum UV index of 5, are months with the highest UV index in Foster City. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for average individuals.
Note: In August, the maximum UV index of 5 translates into these guidelines:
Put precautions into practice - Protective measures against sun-induced damage are advised. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Stay sun-safe with clothing that is both closely woven and worn loosely.
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Frequently asked questions

What is the hottest time of year in Foster City?

Foster City's temperatures tend to hit their maximum during August and September, with an average high-temperature of 71.2°F (21.8°C).

What is the temperature in August in Foster City?

August temperatures in Foster City, California, vary between a high-temperature of 71.2°F (21.8°C) and a low-temperature of 56.3°F (13.5°C).

What are the most humid months in Foster City?

March and August, with an average relative humidity of 76%, are most humid months in Foster City.

What is the average humidity in August in Foster City?

In August, the average relative humidity in Foster City, California, is 76%.

What is the driest month in Foster City?

In Foster City, California, rain does not fall in June through August.

Does it rain in Foster City in August?

In Foster City, California, in August, it doesn't rain. In September, it rains.

How many hours of daylight does Foster City have in August?

In August, the average day length in Foster City, California, is 13h and 34min.

When is the sunrise / sunset in August in Foster City?

On the first day of August in Foster City, sunrise is at 6:13 am and sunset at 8:16 pm. On the last day of the month, sunrise is at 6:39 am and sunset at 7:39 pm PDT.

How many hours of sunshine does Foster City have in August?

In Foster City, the average sunshine duration in August is 11.8h.

When is the highest UV index in Foster City?

The months with the highest UV index are June through September, with an average maximum UV index of 5.

What is the UV index reading in August in Foster City?

The average daily maximum UV index in August is 5. A UV Index value of 3 to 5 symbolizes a medium health risk 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
Foster City, CA

Average temperature in August - Foster City, CA
  • Average high temperature in August: 71.2°F

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).

  • Average low temperature in August: 56.3°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).

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Average pressure in August
Foster City, CA

Average pressure in August - Foster City, CA
  • Average pressure in August: 29.93"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).

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Average wind speed in August
Foster City, CA

Average wind speed in August - Foster City, CA
  • Average wind speed in August: 5.9mph

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).

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Average humidity in August
Foster City, CA

Average humidity in August - Foster City, CA
  • Average humidity in August: 76%

The months with the highest relative humidity are March and August (76%).
The months with the lowest relative humidity are October and November (70%).

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Average rainfall in August
Foster City, CA

Average rainfall in August - Foster City, CA
  • Average rainfall in August: 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").

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Average rainfall days in August
Foster City, CA

Average rainfall days in August - Foster City, CA
  • Average rainfall days in August: 0.7 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).

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Average daylight in August /
Average sunshine in August
Foster City, CA

Average daylight in August / Average sunshine in August - Foster City, 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: 11h and 5min

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).

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Average sunshine days in August
Foster City, CA

Average sunshine days in August - Foster City, CA
  • Average sunshine days in August: 30.2 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).

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Average UV index in August
Foster City, CA

Average UV index in August - Foster City, CA
  • Average UV index in August: 5

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).

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Average cloud cover in August
Foster City, CA

Average cloud cover in August - Foster City, CA
  • Average cloud cover in August: 13

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 11).

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Average visibility in August
Foster City, CA

Average visibility in August - Foster City, 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).

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Foster City, California, USA

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