January weather forecast
Vallejo, CA

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A colorful orange sunset skyline seen over the Napa River and Bridge in Vallejo, California
A colorful orange sunset skyline seen over the Napa River and Bridge in Vallejo, California

Weather in January

January, like December, is another mild winter month in Vallejo, California, with an average temperature fluctuating between 56.5°F (13.6°C) and 43°F (6.1°C).

Temperature

With January's arrival, Vallejo notes an average high-temperature of a still refreshing 56.5°F (13.6°C), closely following the trend of the preceding month. Vallejo's temperature tends to fall to an average low of 43°F (6.1°C) during the nights of January.

Humidity

In January, the average relative humidity is 73%.

Rainfall

In January, the rain falls for 7.7 days. Throughout January, 0.83" (21mm) of precipitation is accumulated. Throughout the year, there are 56.9 rainfall days, and 4.88" (124mm) of precipitation is accumulated.

Daylight

In Vallejo, the average length of the day in January is 9h and 53min.
On the first day of the month, sunrise is at 7:25 am and sunset at 4:59 pm. On the last day of January, sunrise is at 7:14 am and sunset at 5:30 pm PST.

Sunshine

In Vallejo, the average sunshine in January is 5.9h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: A typical high UV index of 3 in January suggests the following recommendations:
Ensure safety - Recommendations to avert sunburn are presented. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.

Frequently asked questions

What are January temperatures?

The high-temperature during January is 56.5°F (13.6°C) and the low-temperature is 43°F (6.1°C).

What is the average humidity in January?

The average relative humidity in January is 73%.

How much does it rain in January?

In Vallejo, in January, it is raining for 7.7 days, with typically 0.83" (21mm) of accumulated precipitation.

What is the average length of the day in January?

In Vallejo, the average day length in January is 9h and 53min.

When are sunrise and sunset in January?

In January, on the first day of the month, sunrise is at 7:25 am and sunset at 4:59 pm. On the last day of the month, sunrise is at 7:14 am and sunset at 5:30 pm PST.

How many hours of sunshine does Vallejo have in January?

In Vallejo, the average sunshine duration in January is 5.9h.

What is the month with the lowest UV index?

January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index.

How high is the UV index in January?

In Vallejo, the average daily maximum UV index in January is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in January
Vallejo, CA

Average temperature in January - Vallejo, CA
  • Average high temperature in January: 56.5°F

The warmest months (with the highest average high temperature) are July and September (80.1°F).
The month with the lowest average high temperature is December (55.4°F).

  • Average low temperature in January: 43°F

The month with the highest average low temperature is August (56.5°F).
The coldest month (with the lowest average low temperature) is January (43°F).

Average pressure in January
Vallejo, CA

Average pressure in January - Vallejo, CA
  • Average pressure in January: 30.14"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in January
Vallejo, CA

Average wind speed in January - Vallejo, CA
  • Average wind speed in January: 4.9mph

The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).

Average humidity in January
Vallejo, CA

Average humidity in January - Vallejo, CA
  • Average humidity in January: 73%

The month with the highest relative humidity is March (75%).
The months with the lowest relative humidity are September and October (60%).

Average rainfall in January
Vallejo, CA

Average rainfall in January - Vallejo, CA
  • Average rainfall in January: 0.83"

The wettest month (with the highest rainfall) is February (1.14").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in January
Vallejo, CA

Average rainfall days in January - Vallejo, CA
  • Average rainfall days in January: 7.7 days

The month with the highest number of rainy days is March (10.2 days).
The month with the least rainy days is August (0.9 days).

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

Average daylight in January / Average sunshine in January - Vallejo, CA
  • Average daylight in January: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in January: 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 42min).

Average sunshine days in January
Vallejo, CA

Average sunshine days in January - Vallejo, CA
  • Average sunshine days in January: 21.8 days

The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (18.8 days).

Average UV index in January
Vallejo, CA

Average UV index in January - Vallejo, CA
  • Average UV index in January: 3

The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in January
Vallejo, CA

Average cloud cover in January - Vallejo, CA
  • Average cloud cover in January: 35

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 9).

Average visibility in January
Vallejo, CA

Average visibility in January - Vallejo, CA
  • Average visibility in January: 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).

Vallejo, California, USA

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