August weather forecastPortola Valley, CA
August
Weather in August
August, the last month of the summer in Portola Valley, is another pleasant month, with an average temperature fluctuating between 56.7°F (13.7°C) and 73°F (22.8°C).Temperature
August registers as the month with the highest average temperatures, reaching 73°F (22.8°C) at its peak and 56.7°F (13.7°C) at the lowest.Humidity
In August, the average relative humidity in Portola Valley, California, is 74%.Rainfall
In Portola Valley, California, in August, during 1 rainfall days, 0.08" (2mm) of precipitation is typically accumulated. In Portola Valley, during the entire year, the rain falls for 57.5 days and collects up to 4.76" (121mm) of precipitation.Daylight
In Portola Valley, California, the average length of the day in August is 13h and 33min.On the first day of the month, sunrise is at 6:14 am and sunset at 8:16 pm. On the last day of August, sunrise is at 6:39 am and sunset at 7:38 pm PDT.
Sunshine
In Portola Valley, the average sunshine in August is 11.9h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: The UV index of 5 during August translates into the following guidance:
Make use of precautions - Suggestions to resist sunburn are communicated. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Portola Valley, CA
- Average high temperature in August: 73°F
The warmest month (with the highest average high temperature) is August (73°F).
The month with the lowest average high temperature is December (55.8°F).
- Average low temperature in August: 56.7°F
The months with the highest average low temperature are August and September (56.7°F).
The coldest months (with the lowest average low temperature) are January and February (46.4°F).
Average pressure in August
Portola Valley, 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).
Average wind speed in August
Portola Valley, CA
- Average wind speed in August: 5.5mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).
Average humidity in August
Portola Valley, CA
- Average humidity in August: 74%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is October (68%).
Average rainfall in August
Portola Valley, CA
- Average rainfall in August: 0.08"
The wettest month (with the highest rainfall) is February (0.98").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in August
Portola Valley, CA
- Average rainfall days in August: 1 days
The month with the highest number of rainy days is March (10.6 days).
The month with the least rainy days is June (0.9 days).
Average daylight in August /
Average sunshine in August
Portola Valley, CA
- Average daylight in August: 13h and 36min
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 54min
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).
Average sunshine days in August
Portola Valley, CA
- Average sunshine days in August: 24.2 days
The months with the most sunshine days are June and July (26.3 days).
The month with the least sunshine days is March (18.3 days).
Average UV index in August
Portola Valley, 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, November and December (UV index 3).
Average cloud cover in August
Portola Valley, CA
- Average cloud cover in August: 11
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in August
Portola Valley, 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).
