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Contents
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
Weather in January
January, the same as December, in Portola Valley, California, is another mild winter month, with an average temperature varying between 56.7°F (13.7°C) and 46.4°F (8°C). With January's advent, Portola Valley sees an average high-temperature of a still mild 56.7°F (13.7°C), subtly shifted from December's 55.8°F (13.2°C). Weather in January »
Weather in February
The last month of the winter, February, is another refreshing month in Portola Valley, California, with an average temperature varying between 46.4°F (8°C) and 58.3°F (14.6°C). In February, Portola Valley experiences a barely noticeable shift in meteorological conditions, with average high-temperatures moving from 56.7°F (13.7°C) in January to a still refreshing 58.3°F (14.6°C). Weather in February »
Weather in March
March, the first month of the spring in Portola Valley, is also a moderate month, with temperature in the range of an average high of 59.5°F (15.3°C) and an average low of 46.9°F (8.3°C). Portola Valley's transition from February to March introduces an average high-temperature of a still refreshing 59.5°F (15.3°C), marking an insignificant variation from the 58.3°F (14.6°C). Weather in March »
Weather in April
April in Portola Valley, California, is a refreshing spring month, with temperature in the range of an average high of 62.2°F (16.8°C) and an average low of 48.2°F (9°C). In April, Portola Valley's weather conditions record an average high-temperature of a comfortable 62.2°F (16.8°C), demonstrating little divergence from the preceding month. Weather in April »
Weather in May
The last month of the spring, May, is another comfortable month in Portola Valley, California, with an average temperature fluctuating between 64.9°F (18.3°C) and 50.2°F (10.1°C). Portola Valley in May witnesses an average high-temperature of a still enjoyable 64.9°F (18.3°C), indicating a slight variation from April's 62.2°F (16.8°C). Weather in May »
Weather in June
The first month of the summer, June, is a pleasant month in Portola Valley, California, with an average temperature varying between 70°F (21.1°C) and 53.4°F (11.9°C). Portola Valley's average high-temperature marks a pleasant 70°F (21.1°C) with the advent of June, closely mirroring that of the preceding month. Weather in June »
Weather in July
July, the same as June, in Portola Valley, California, is another pleasant summer month, with temperature in the range of an average low of 54.7°F (12.6°C) and an average high of 72.7°F (22.6°C). Portola Valley, California, sees the arrival of July with an average high-temperature of a still agreeable 72.7°F (22.6°C), indicating a subtle variation from June. Weather in July »
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). 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. Weather in August »
Weather in September
September, the first month of the autumn in Portola Valley, is also an agreeable month, with an average temperature ranging between min 56.7°F (13.7°C) and max 72.5°F (22.5°C). In September, the average high-temperature registers at a still pleasant 72.5°F (22.5°C), nearly identical to August's 73°F (22.8°C). Weather in September »
Weather in October
October, the same as September, in Portola Valley, California, is an agreeable autumn month, with an average temperature varying between 68.2°F (20.1°C) and 54.9°F (12.7°C). 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. Weather in October »
Weather in November
The last month of the autumn, November, is another refreshing month in Portola Valley, California, with an average temperature fluctuating between 61.9°F (16.6°C) and 50.5°F (10.3°C). November brings a minor shift in the average high-temperature, adjusting from a pleasant 68.2°F (20.1°C) in October to a comfortable 61.9°F (16.6°C). Weather in November »
Weather in December
The first month of the winter, December, is still a refreshing month in Portola Valley, California, with an average temperature fluctuating between 47.1°F (8.4°C) and 55.8°F (13.2°C). December is the coldest month, exhibiting average temperatures of 55.8°F (13.2°C) at the peak and 47.1°F (8.4°C) at the base. Weather in December »
Updated: Feb 9, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How many days does it rain in Portola Valley?
In Portola Valley, California, during the entire year, the rain falls for 57.5 days and collects up to 4.76" (121mm) of precipitation.
What is the wettest month in Portola Valley?
February is the month with the most rainfall in Portola Valley, California. Rain falls for 6.6 days and accumulates 0.98" (25mm) of precipitation.
When is the lowest UV index in Portola Valley?
February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in Portola Valley, California.
What is the most humid month in Portola Valley?
With an average relative humidity of 76%, March is the most humid month in Portola Valley, California.
When is Daylight Saving Time (DST) in Portola Valley?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Portola Valley, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.
What is the driest month in Portola Valley?
June is the month with the least rainfall. Rain falls for 0.9 days and accumulates 0.04" (1mm) of precipitation.
When are the longest days in Portola Valley?
June has the longest days of the year in Portola Valley, California, with an average of 14h and 42min of daylight.
What is the month with the highest UV index in Portola Valley?
The months with the highest UV index are June through September, with an average maximum UV index of 5.
What month has the most sunshine in Portola Valley?
With an average of 12h of sunshine, July has the most sunshine of the year in Portola Valley, California.
What part of the year is the hottest in Portola Valley?
During the warmest month in Portola Valley, August, temperatures average a high of 73°F (22.8°C) and a low of 56.7°F (13.7°C).
What is the least humid month in Portola Valley?
October is the least humid month in Portola Valley, with an average relative humidity of 68%.
What is the coldest month in Portola Valley?
Portola Valley's coldest temperatures are experienced in December, with average high temperatures of 55.8°F (13.2°C) and lows of 47.1°F (8.4°C).
What is the month with the shortest days in Portola Valley?
The month with the shortest days in Portola Valley, California, is December, with an average of 9h and 36min of daylight.
What is the month with the least sunshine in Portola Valley?
December has the least sunshine of the year, with an average of 5.9h of sunshine.
Average temperature
Portola Valley, CA
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).
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
Portola Valley, CA
- Average pressure in January:
30.13"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
30.04"Hg - Average pressure in May:
29.98"Hg - Average pressure in June:
29.93"Hg
- Average pressure in July:
29.94"Hg - Average pressure in August:
29.93"Hg - Average pressure in September:
29.92"Hg - Average pressure in October:
29.99"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.11"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
Portola Valley, CA
- Average wind speed in January:
6mph - Average wind speed in February:
7.3mph - Average wind speed in March:
7.4mph - Average wind speed in April:
7.6mph - Average wind speed in May:
7.5mph - Average wind speed in June:
6.8mph
- Average wind speed in July:
5.7mph - Average wind speed in August:
5.5mph - Average wind speed in September:
5.7mph - Average wind speed in October:
5.7mph - Average wind speed in November:
6mph - Average wind speed in December:
6.6mph
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
Portola Valley, CA
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is October (68%).
Average rainfall
Portola Valley, CA
- Average rainfall in January:
0.67" - Average rainfall in February:
0.98" - Average rainfall in March:
0.83" - Average rainfall in April:
0.24" - Average rainfall in May:
0.31" - Average rainfall in June:
0.04"
- Average rainfall in July:
0.08" - Average rainfall in August:
0.08" - Average rainfall in September:
0.08" - Average rainfall in October:
0.12" - Average rainfall in November:
0.55" - Average rainfall in December:
0.79"
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
Portola Valley, CA
- Average rainfall days in January:
7.8 days - Average rainfall days in February:
6.6 days - Average rainfall days in March:
10.6 days - Average rainfall days in April:
5.8 days - Average rainfall days in May:
3.8 days - Average rainfall days in June:
0.9 days
- Average rainfall days in July:
1.5 days - Average rainfall days in August:
1 days - Average rainfall days in September:
2.4 days - Average rainfall days in October:
3.3 days - Average rainfall days in November:
4.9 days - Average rainfall days in December:
8.9 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 / Average sunshine
Portola Valley, CA
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 5min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 1min - Average daylight in May:
14h and 1min - Average daylight in June:
14h and 4min
- Average daylight in July:
14h and 2min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 1min - Average daylight in December:
9h 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 January:
6h and 2min - Average sunshine in February:
6h and 2min - Average sunshine in March:
7h and 5min - Average sunshine in April:
10h and 2min - Average sunshine in May:
10h and 4min - Average sunshine in June:
11h and 4min
- Average sunshine in July:
12h and 0min - Average sunshine in August:
11h and 5min - Average sunshine in September:
11h and 0min - Average sunshine in October:
7h and 1min - Average sunshine in November:
6h and 4min - Average sunshine in December:
5h 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).
Average sunshine days
Portola Valley, CA
- Average sunshine days in January:
21.8 days - Average sunshine days in February:
19.3 days - Average sunshine days in March:
18.3 days - Average sunshine days in April:
22.2 days - Average sunshine days in May:
22.9 days - Average sunshine days in June:
26.3 days
- Average sunshine days in July:
26.3 days - Average sunshine days in August:
24.2 days - Average sunshine days in September:
25.8 days - Average sunshine days in October:
25.4 days - Average sunshine days in November:
23.8 days - Average sunshine days in December:
20.4 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
Portola Valley, CA
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
Portola Valley, CA
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
Portola Valley, CA
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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