Contents
- Weather in October
- Frequently asked questions
- Average temperature in October
- Average pressure in October
- Average wind speed in October
- Average humidity in October
- Average rainfall in October
- Average rainfall days in October
- Average daylight in October
- Average sunshine in October
- Average sunshine days in October
- Average UV index in October
- Average cloud cover in October
- Average visibility in October
Weather in October
Temperature
Portola Valley greets October with an average high-temperature of a still pleasant 68.2°F (20.1°C), marking a slight deviation from the preceding month. During October nights, Portola Valley records an average temperature of 54.9°F (12.7°C).Humidity
The least humid month is October, with an average relative humidity of 68%.Rainfall
In Portola Valley, in October, during 3.3 rainfall days, 0.12" (3mm) of precipitation is typically accumulated. Throughout the year, there are 57.5 rainfall days, and 4.76" (121mm) of precipitation is accumulated.Daylight
In October, the average length of the day is 11h and 13min.On the first day of October, sunrise is at 7:05 am and sunset at 6:51 pm. On the last day of the month, sunrise is at 7:33 am and sunset at 6:11 pm PDT.
Sunshine
The average sunshine in October in Portola Valley, California, is 7.1h.UV index
In October, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: The daily high UV index of 4 during October translates into the following recommendations:
Take precautions - Protection against skin and eye damage is obliged. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Portola Valley in October?
What is the least humid month in Portola Valley?
What is the average humidity in October in Portola Valley?
How many days does it rain in October in Portola Valley?
How many hours of daylight does Portola Valley have in October?
When are sunrise and sunset in October in Portola Valley?
How many hours of sunshine does Portola Valley have in October?
What is the UV index reading in October in Portola Valley?
Average temperature in October
Portola Valley, CA
- Average high temperature in October: 68.2°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 October: 54.9°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 October
Portola Valley, CA
- Average pressure in October: 29.99"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 October
Portola Valley, CA
- Average wind speed in October: 5.7mph
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 October
Portola Valley, CA
- Average humidity in October: 68%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is October (68%).
Average rainfall in October
Portola Valley, CA
- Average rainfall in October: 0.12"
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 October
Portola Valley, CA
- Average rainfall days in October: 3.3 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 October /
Average sunshine in October
Portola Valley, CA
- Average daylight in October: 11h and 1min
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 October: 7h and 1min
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 October
Portola Valley, CA
- Average sunshine days in October: 25.4 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 October
Portola Valley, CA
- Average UV index in October: 4
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 October
Portola Valley, CA
- Average cloud cover in October: 16
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 October
Portola Valley, CA
- Average visibility in October: 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).
Portola Valley, California, USA
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