January weather forecast
Portola, CA

Share

Weather in January

January, the same as December, is another cold winter month in Portola, California, with an average temperature fluctuating between 23.2°F (-4.9°C) and 38.8°F (3.8°C).

Temperature

Portola's shift from December to January is accompanied by an average high-temperature of a still cold 38.8°F (3.8°C), a slight deviation from 37.2°F (2.9°C). The nighttime temperature, during January, averages 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, during 6.8 rainfall days, 3.62" (92mm) of precipitation is typically accumulated. Throughout the year, there are 80.1 rainfall days, and 22.95" (583mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through June, September through December. In Portola, in January, snow falls for 10.5 days, with typically accumulated 19.09" (485mm) of snow. Throughout the year, in Portola, there are 69.3 snowfall days, and 103.5" (2629mm) of snow is accumulated.

Daylight

The average length of the day in January is 9h and 44min.
On the first day of January, 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 in Portola is January, with an average of 5h of sunshine.

UV index

In Portola, the average daily maximum UV index in January is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: The maximum daily UV index of 2 in January interprets into the following recommendations:
Sun exposure does not present considerable issues for many, yet infants, fair-skinned people, and children necessitate constant protection. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
[Resources]

Frequently asked questions

Is January cold in Portola?

Portola in January has an average high-temperature of 38.8°F (3.8°C) and an average low-temperature of 23.2°F (-4.9°C).

What is the most humid month in Portola?

The months with the highest humidity in Portola, California, are January and March, with an average relative humidity of 81%.

What is the average humidity in January in Portola?

The average relative humidity in January is 81%.

How many days does it rain in January in Portola?

In Portola, California, during January, the rain falls for 6.8 days and regularly aggregates up to 3.62" (92mm) of precipitation.

How much does it snow in Portola in January?

In Portola, in January, during 10.5 snowfall days, 19.09" (485mm) of snow is typically accumulated.

What is the average length of the day in January in Portola?

In January, the average day length in Portola is 9h and 44min.

What time are sunrise and sunset in January in Portola?

On the first day of January in Portola, California, 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.

What is the month with the least sunshine in Portola?

January has the least sunshine of the year in Portola, California, with an average of 5h of sunshine.

How many hours of sunshine does Portola have in January?

In January, the average sunshine duration in Portola is 5h.

How high is the UV index in January in Portola?

In Portola, California, the average daily maximum UV index in January is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in January
Portola, CA

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).

[Resources]

Average pressure in January
Portola, CA

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).

[Resources]

Average wind speed in January
Portola, CA

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).

[Resources]

Average humidity in January
Portola, CA

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%).

[Resources]

Average rainfall in January
Portola, CA

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").

[Resources]

Average rainfall days in January
Portola, CA

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).

[Resources]

Average snowfall in January
Portola, CA

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").

[Resources]

Average snowfall days in January
Portola, CA

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).

[Resources]

Average daylight in January /
Average sunshine in January
Portola, CA

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).

[Resources]

Average sunshine days in January
Portola, CA

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).

[Resources]

Average UV index in January
Portola, CA

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).

[Resources]

Average cloud cover in January
Portola, CA

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).

[Resources]

Average visibility in January
Portola, CA

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).

[Resources]

Portola, California, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location