January weather forecast and climate
Fullerton, CA

Trees and neat lawns of the famous Muckenthaler Community Center in Fullerton, California
Trees and neat lawns of the famous Muckenthaler Community Center in Fullerton, California

Weather in January

January, the same as December, is another comfortable winter month in Fullerton, California, with average temperature ranging between max 66.2°F (19°C) and min 51.4°F (10.8°C).

Temperature

In January, the average high-temperature is practically the same as in December - a still comfortable 66.2°F (19°C). In Fullerton, the average low-temperature is 51.4°F (10.8°C).

Humidity

In January, the average relative humidity is 54%.

Rainfall

In Fullerton, in January, it is raining for 4.8 days, with typically 1.14" (29mm) of accumulated precipitation. Throughout the year, there are 52.5 rainfall days, and 7.09" (180mm) of precipitation is accumulated.

Daylight

In January, the average length of the day in Fullerton is 10.2h.

Sunshine

The average sunshine in Fullerton is 6.9h.

UV index

January, February, November and December, with an average maximum UV index of 4, are months with the lowest UV index in Fullerton. A UV Index value of 3 to 5 symbolizes a moderate threat to health from the exposure to the Sun's UV radiation for the ordinary person.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in January in Fullerton?

In January, in Fullerton, California, the average high-temperature is 66.2°F (19°C), and the average low-temperature is 51.4°F (10.8°C).

What is the average humidity in January in Fullerton?

In Fullerton, California, the average relative humidity in January is 54%.

How much does it rain in Fullerton in January?

In Fullerton, California, during January, the rain falls for 4.8 days and regularly aggregates up to 1.14" (29mm) of precipitation.

How many hours of daylight does Fullerton have in January?

In Fullerton, the average length of the day in January is 10.2h.

How long on average sun shines in January in Fullerton?

The average sunshine in January is 6.9h.

When is the lowest UV index in Fullerton?

Months with the lowest UV index in Fullerton, California, are January, February, November and December, with an average maximum UV index of 4.

What is the UV index reading in January in Fullerton?

In Fullerton, California, the average daily maximum UV index in January is 4. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to the Sun's UV rays.

Average temperature in January
Fullerton, CA

Average temperature in January - Fullerton, CA
  • Average high temperature in January: 66.2°F

The warmest month (with the highest average high temperature) is August (83.5°F).
The month with the lowest average high temperature is December (64°F).

  • Average low temperature in January: 51.4°F

The month with the highest average low temperature is August (65.5°F).
The coldest month (with the lowest average low temperature) is February (50.2°F).

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Average pressure in January
Fullerton, CA

Average pressure in January - Fullerton, CA
  • Average pressure in January: 30.1"

The month with the highest atmospheric pressure is January (30.1").
The month with the lowest atmospheric pressure is June (29.88").

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Average wind speed in January
Fullerton, CA

Average wind speed in January - Fullerton, CA
  • Average wind speed in January: 5.2mph

The windiest month (with the highest average wind speed) is April (6mph).
The calmest months (with the lowest average wind speed) are September and October (4.7mph).

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Average humidity in January
Fullerton, CA

Average humidity in January - Fullerton, CA
  • Average humidity in January: 54%

The month with the highest relative humidity is June (65%).
The month with the lowest relative humidity is November (51%).

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Average rainfall in January
Fullerton, CA

Average rainfall in January - Fullerton, CA
  • Average rainfall in January: 1.14"

The wettest month (with the highest rainfall) is December (1.54").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in January
Fullerton, CA

Average rainfall days in January - Fullerton, CA
  • Average rainfall days in January: 4.8 days

The month with the highest number of rainy days is March (7.3 days).
The month with the least rainy days is June (1.5 days).

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

Average daylight in January / Average sunshine in January - Fullerton, CA
  • Average daylight in January: 10.2h

The month with the longest days is June (Average daylight: 14.4h).
The month with the shortest days is December (Average daylight: 9.9h).

  • Average sunshine in January: 6.9h

Months with the most sunshine are July and August (Average sunshine: 12h).
The month with the least sunshine is December (Average sunshine: 6.7h).

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Average sunshine days in January
Fullerton, CA

Average sunshine days in January - Fullerton, CA
  • Average sunshine days in January: 25.2 days

The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is February (20.6 days).

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Average UV index in January
Fullerton, CA

Average UV index in January - Fullerton, CA
  • Average UV index in January: 4

Months with the highest UV index are June, July, August and September (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 4).

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Average cloud cover in January
Fullerton, CA

Average cloud cover in January - Fullerton, CA
  • Average cloud cover in January: 20

Months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in January
Fullerton, CA

Average visibility in January - Fullerton, CA
  • Average visibility in January: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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