December weather forecast
Norwalk, CA

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Weather in December

December completes the annual weather cycle in Norwalk, reverting to colder temperatures typical of the winter season. An average high of no more than 64.6°F (18.1°C) coupled with increased rainfall of 1.46" (37mm) highlights the return of the colder months. With extended cloud cover and increased relative humidity, this month presents more gray days than usual. Despite having the highest rainfall in the year, December retains good visibility, offering clear views of the city's winter landscape. The weather in December, with its bitingly cold winds and frequent rainfall, truly embodies a Californian winter.

Temperature

Norwalk's coldest month, December, generally records average temperatures ranging from a high of 64.6°F (18.1°C) to a low of 51.1°F (10.6°C).

Humidity

In Norwalk, the average relative humidity in December is 55%.

Rainfall

December is the month with the most rainfall. Rain falls for 6.1 days and accumulates 1.46" (37mm) of precipitation.

Daylight

With an average of 9h and 54min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 6:39 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 4:54 pm PST.

Sunshine

The month with the least sunshine is December, with an average of 6.7h of sunshine.

UV index

February, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for average individuals.
Note: The average daily UV index of 4 in December transforms into the following instructions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. To avoid the Sun's strongest rays, limit exposure around the mid-day period. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Updated: Aug 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the coldest months?

December is the month when Norwalk experiences its coldest temperatures, averaging a high of 64.6°F (18.1°C) and a low of 51.1°F (10.6°C).

What is the usual temperature for Norwalk in December?

Norwalk in December has an average high-temperature of 64.6°F (18.1°C) and an average low-temperature of 51.1°F (10.6°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in September is evaluated at 84.2°F (29°C).

What is the average humidity in December?

In December, the average relative humidity is 55%.

What is the rainiest month?

The month with the most rainfall is December, when the rain falls for 6.1 days and typically aggregates up to 1.46" (37mm) of precipitation.

How many days does it rain in December?

In Norwalk, in December, during 6.1 rainfall days, 1.46" (37mm) of precipitation is typically accumulated.

What is the month with the shortest days in Norwalk?

The month with the shortest days is December, with an average of 9h and 54min of daylight.

How many hours of daylight does Norwalk have in December?

In December, the average day length is 9h and 56min.

What time are sunrise and sunset in December in Norwalk?

In December, on the first day of the month, sunrise is at 6:39 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 4:54 pm PST.

What is the month with the least sunshine?

December has the least sunshine of the year, with an average of 6.7h of sunshine.

How long on average sun shines in December?

The average sunshine duration in December is 6.7h.

What are the months with the lowest UV index?

The months with the lowest UV index are February, November and December, with an average maximum UV index of 4.

What is the UV index reading in December?

In Norwalk, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a medium hazard to health from exposure to the Sun's 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 December
Norwalk, CA

Average temperature in December - Norwalk, CA
  • Average high temperature in December: 64.6°F

The warmest month (with the highest average high temperature) is August (83.1°F).
The month with the lowest average high temperature is December (64.6°F).

  • Average low temperature in December: 51.1°F

The month with the highest average low temperature is August (65.7°F).
The coldest month (with the lowest average low temperature) is February (50.5°F).

Average pressure in December
Norwalk, CA

Average pressure in December - Norwalk, CA
  • Average pressure in December: 30.07"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are June and September (29.89"Hg).

Average wind speed in December
Norwalk, CA

Average wind speed in December - Norwalk, CA
  • Average wind speed in December: 5.3mph

The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is October (4.7mph).

Average humidity in December
Norwalk, CA

Average humidity in December - Norwalk, CA
  • Average humidity in December: 55%

The month with the highest relative humidity is June (66%).
The month with the lowest relative humidity is November (51%).

Average rainfall in December
Norwalk, CA

Average rainfall in December - Norwalk, CA
  • Average rainfall in December: 1.46"

The wettest month (with the highest rainfall) is December (1.46").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in December
Norwalk, CA

Average rainfall days in December - Norwalk, CA
  • Average rainfall days in December: 6.1 days

The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).

Average daylight in December /
Average sunshine in December
Norwalk, CA

Average daylight in December / Average sunshine in December - Norwalk, CA
  • Average daylight in December: 9h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in December: 6h and 4min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).

Average sunshine days in December
Norwalk, CA

Average sunshine days in December - Norwalk, CA
  • Average sunshine days in December: 23.4 days

The months with the most sunshine days are January and August (25.6 days).
The month with the least sunshine days is February (21.1 days).

Average UV index in December
Norwalk, CA

Average UV index in December - Norwalk, CA
  • Average UV index in December: 4

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

Average cloud cover in December
Norwalk, CA

Average cloud cover in December - Norwalk, CA
  • Average cloud cover in December: 22

The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 6).

Average visibility in December
Norwalk, CA

Average visibility in December - Norwalk, CA
  • Average visibility in December: 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).

Norwalk, California, USA

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