Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
December, having an average high-temperature of 63.7°F (17.6°C) and an average low-temperature of 47.7°F (8.7°C), is the coldest month.Humidity
In December, the average relative humidity in Walnut is 51%.Rainfall
The month with the most rainfall is December, when the rain falls for 5.4 days and typically aggregates up to 1.57" (40mm) of precipitation.Daylight
The month with the shortest days in Walnut is December, with an average of 9h and 54min of daylight.On the first day of the month, sunrise is at 6:39 am and sunset at 4:42 pm. On the last day of December, sunrise is at 6:56 am and sunset at 4:52 pm PST.
Sunshine
In Walnut, the average sunshine in December is 6.9h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for average individuals.Note: The maximum UV index of 4 during December translates into these guidelines:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest time of year?
What is the average December temperature?
What is the average humidity in December?
What is the wettest month?
How many days does it rain in December?
What is the month with the shortest days in Walnut?
What is the average length of the day in December?
When are sunrise and sunset in December?
How long on average sun shines in December?
What are the months with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Walnut, CA
- Average high temperature in December: 63.7°F
The warmest month (with the highest average high temperature) is August (89.2°F).
The month with the lowest average high temperature is December (63.7°F).
- Average low temperature in December: 47.7°F
The month with the highest average low temperature is August (66.2°F).
The coldest months (with the lowest average low temperature) are February and December (47.7°F).
Average pressure in December
Walnut, CA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in December
Walnut, CA
- Average wind speed in December: 5mph
The windiest months (with the highest average wind speed) are April and May (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).
Average humidity in December
Walnut, CA
- Average humidity in December: 51%
The months with the highest relative humidity are May and June (56%).
The month with the lowest relative humidity is November (45%).
Average rainfall in December
Walnut, CA
- Average rainfall in December: 1.57"
The wettest month (with the highest rainfall) is December (1.57").
The driest months (with the least rainfall) are June and August (0.04").
Average rainfall days in December
Walnut, CA
- Average rainfall days in December: 5.4 days
The month with the highest number of rainy days is March (6.6 days).
The month with the least rainy days is June (1 days).
Average daylight in December /
Average sunshine in December
Walnut, 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 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is February (Average sunshine: 6h and 48min).
Average sunshine days in December
Walnut, CA
- Average sunshine days in December: 24.4 days
The month with the most sunshine days is June (28.6 days).
The month with the least sunshine days is February (22 days).
Average UV index in December
Walnut, CA
- Average UV index in December: 4
The months with the highest UV index are July and August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 4).
Average cloud cover in December
Walnut, CA
- Average cloud cover in December: 21
The months with the most cloud cover are February, March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Walnut, 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).
Walnut, California, USA
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