August weather forecast
Vallejo, CA

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A colorful orange sunset skyline seen over the Napa River and Bridge in Vallejo, California
A colorful orange sunset skyline seen over the Napa River and Bridge in Vallejo, California

Weather in August

The last month of the summer, August, is another warm month in Vallejo, California, with an average temperature fluctuating between 56.5°F (13.6°C) and 79.7°F (26.5°C).

Temperature

The advent of August brings an average high-temperature of a still warm 79.7°F (26.5°C), almost identical to the preceding month. In Vallejo, August nights witness a remarkable decline from the day's zenith to a mild 56.5°F (13.6°C).

Humidity

The average relative humidity in August is 65%.

Rainfall

The months with the least rainfall are July and August Rain falls for 0.9 days and accumulates 0.04" (1mm) of rain.

Daylight

In Vallejo, the average length of the day in August is 13h and 35min.
On the first day of the month, sunrise is at 6:12 am and sunset at 8:18 pm. On the last day of August, sunrise is at 6:38 am and sunset at 7:39 pm PDT.

Sunshine

In Vallejo, the average sunshine in August is 11.9h.

UV index

In August, the average daily maximum UV index 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, a daily UV index of 5 turns into the following recommendations:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.

Frequently asked questions

What is the usual temperature for Vallejo in August?

In Vallejo, 79.7°F (26.5°C) is the average high-temperature and 56.5°F (13.6°C) is the average low-temperature during August.

What is the average humidity in August?

In Vallejo, the average relative humidity in August is 65%.

What is the driest month?

July and August are months with the least rain when the rain falls for 0.9 days and typically aggregates up to 0.04" (1mm) of rain.

How much does it rain in Vallejo in August?

In August, the rain falls for 0.9 days. Throughout August, 0.04" (1mm) of precipitation is accumulated.

How many hours of daylight does Vallejo have in August?

In August, the average day length in Vallejo is 13h and 35min.

When is the sunrise / sunset in August?

On the first day of August, sunrise is at 6:12 am and sunset at 8:18 pm. On the last day of the month, sunrise is at 6:38 am and sunset at 7:39 pm PDT.

How many hours of sunshine does Vallejo have in August?

In August, the average sunshine duration is 11.9h.

What is the UV index reading in August?

In Vallejo, the average daily maximum UV index in August is 5. A UV Index reading of 3 to 5 represents a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Vallejo, CA

Average temperature in August - Vallejo, CA
  • Average high temperature in August: 79.7°F

The warmest months (with the highest average high temperature) are July and September (80.1°F).
The month with the lowest average high temperature is December (55.4°F).

  • Average low temperature in August: 56.5°F

The month with the highest average low temperature is August (56.5°F).
The coldest month (with the lowest average low temperature) is January (43°F).

Average pressure in August
Vallejo, CA

Average pressure in August - Vallejo, CA
  • Average pressure in August: 29.92"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in August
Vallejo, CA

Average wind speed in August - Vallejo, CA
  • Average wind speed in August: 6.2mph

The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).

Average humidity in August
Vallejo, CA

Average humidity in August - Vallejo, CA
  • Average humidity in August: 65%

The month with the highest relative humidity is March (75%).
The months with the lowest relative humidity are September and October (60%).

Average rainfall in August
Vallejo, CA

Average rainfall in August - Vallejo, CA
  • Average rainfall in August: 0.04"

The wettest month (with the highest rainfall) is February (1.14").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in August
Vallejo, CA

Average rainfall days in August - Vallejo, CA
  • Average rainfall days in August: 0.9 days

The month with the highest number of rainy days is March (10.2 days).
The month with the least rainy days is August (0.9 days).

Average daylight in August /
Average sunshine in August
Vallejo, CA

Average daylight in August / Average sunshine in August - Vallejo, CA
  • Average daylight in August: 13h and 4min

The month with the longest days is June (Average daylight: 14h and 48min).
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 42min).

Average sunshine days in August
Vallejo, CA

Average sunshine days in August - Vallejo, CA
  • Average sunshine days in August: 25.8 days

The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (18.8 days).

Average UV index in August
Vallejo, CA

Average UV index in August - Vallejo, 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 January, February, November and December (UV index 3).

Average cloud cover in August
Vallejo, CA

Average cloud cover in August - Vallejo, CA
  • Average cloud cover in August: 11

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 9).

Average visibility in August
Vallejo, CA

Average visibility in August - Vallejo, 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).

Vallejo, California, USA

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