Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average snowfall in January
- Average snowfall days in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
January's presence records an average high-temperature of a still icy 38.8°F (3.8°C), closely mirroring December's climate. Throughout the January nights, Portola encounters a low-temperature of 23.2°F (-4.9°C).Humidity
January and March, with an average relative humidity of 81%, are the most humid months.Rainfall
In Portola, in January, it is raining for 6.8 days, with typically 3.62" (92mm) of accumulated precipitation. Throughout the year, in Portola, there are 80.1 rainfall days, and 22.95" (583mm) of precipitation is accumulated.Snowfall
January through June, September through December are months with snowfall. In January, in Portola, it is snowing for 10.5 days. Throughout January, 19.09" (485mm) of snow is accumulated. Throughout the year, there are 69.3 snowfall days, and 103.5" (2629mm) of snow is accumulated.Daylight
In Portola, the average length of the day in January is 9h and 44min.On the first day of January in Portola, sunrise is at 7:23 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 5:19 pm PST.
Sunshine
The month with the least sunshine is January, with an average of 5h of sunshine.UV index
The average daily maximum UV index in January is 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: The daily maximum UV index of 2 in January interprets into the following advice:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Avoiding the Sun during its peak radiation time around midday is a healthy practice. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Note well! The intensity of the Sun's UV rays can be nearly doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is January?
What are the most humid months?
What is the average humidity in January?
How many days does it rain in January?
How much does it snow in January?
What is the average length of the day in January?
What time are sunrise and sunset in January in Portola?
What is the month with the least sunshine?
How long on average sun shines in January?
What is the UV index intensity in January?
Average temperature in January
Portola, CA
- Average high temperature in January: 38.8°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is December (37.2°F).
- Average low temperature in January: 23.2°F
The month with the highest average low temperature is July (47.5°F).
The coldest month (with the lowest average low temperature) is December (21.6°F).
Average pressure in January
Portola, CA
- Average pressure in January: 30.19"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in January
Portola, CA
- Average wind speed in January: 5.7mph
The windiest month (with the highest average wind speed) is March (6.6mph).
The calmest months (with the lowest average wind speed) are August and September (5.2mph).
Average humidity in January
Portola, CA
- Average humidity in January: 81%
The months with the highest relative humidity are January and March (81%).
The months with the lowest relative humidity are July and August (40%).
Average rainfall in January
Portola, CA
- Average rainfall in January: 3.62"
The wettest month (with the highest rainfall) is March (4.02").
The driest month (with the least rainfall) is August (0.2").
Average rainfall days in January
Portola, CA
- Average rainfall days in January: 6.8 days
The month with the highest number of rainy days is May (11.8 days).
The month with the least rainy days is July (3.3 days).
Average snowfall in January
Portola, CA
- Average snowfall in January: 19.09"
The month with the highest snowfall is December (22.52").
The months with the least snowfall are July and August (0").
Average snowfall days in January
Portola, CA
- Average snowfall days in January: 10.5 days
The month with the highest number of snowfall days is March (14.7 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in January /
Average sunshine in January
Portola, CA
- Average daylight in January: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in January: 5h
The month with the most sunshine is July (Average sunshine: 12h).
The month with the least sunshine is January (Average sunshine: 5h).
Average sunshine days in January
Portola, CA
- Average sunshine days in January: 16.8 days
The month with the most sunshine days is August (26 days).
The month with the least sunshine days is March (11.8 days).
Average UV index in January
Portola, CA
- Average UV index in January: 2
The months with the highest UV index are June, July and August (UV index 5).
The month with the lowest UV index is November (UV index 1).
Average cloud cover in January
Portola, CA
- Average cloud cover in January: 45
The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility in January
Portola, CA
- Average visibility in January: 4mi
The months with the highest visibility are May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (4mi).
Portola, California, USA
Weather forecast for your location
2. Allow the app to use your location