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 snowfall in December
- Average snowfall 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
The coldest time of the year is December, with temperatures averaging a high of 54.5°F (12.5°C) and a low of 39.6°F (4.2°C).Humidity
In Saint Helena, the average relative humidity in December is 73%.Rainfall
In December, the rain falls for 11.3 days. Throughout December, 2.95" (75mm) of precipitation is accumulated. Throughout the year, in Saint Helena, there are 76.2 rainfall days, and 16.93" (430mm) of precipitation is accumulated.Snowfall
January, February, April through December are months without snowfall in Saint Helena, California.Daylight
December has the shortest days of the year in Saint Helena, with an average of 9h and 30min of daylight.On the first day of December, sunrise is at 7:09 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:59 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 5.3h of sunshine.UV index
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in Saint Helena. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for average individuals.Note: The UV index of 3 during December translates into the following guidance:
Heed the precautions - Suggestions to avoid sunburn are made. When the Sun is at its strongest around midday, find shade and limit exposure. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat.
Frequently asked questions
What is the coldest month in Saint Helena?
What are December temperatures in Saint Helena?
What is the average humidity in December in Saint Helena?
How much does it rain in Saint Helena in December?
When it does not snow in Saint Helena?
What is the month with the shortest days in Saint Helena?
How many hours of daylight does Saint Helena have in December?
When are sunrise and sunset in December in Saint Helena?
What is the month with the least sunshine in Saint Helena?
How long on average sun shines in December in Saint Helena?
What are the months with the lowest UV index in Saint Helena?
What is the UV index reading in December in Saint Helena?
Average temperature in December
Saint Helena, CA
- Average high temperature in December: 54.5°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (54.5°F).
- Average low temperature in December: 39.6°F
The month with the highest average low temperature is September (54.3°F).
The coldest month (with the lowest average low temperature) is December (39.6°F).
Average pressure in December
Saint Helena, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).
Average wind speed in December
Saint Helena, CA
- Average wind speed in December: 4.6mph
The windiest month (with the highest average wind speed) is May (5.8mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).
Average humidity in December
Saint Helena, CA
- Average humidity in December: 73%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (53%).
Average rainfall in December
Saint Helena, CA
- Average rainfall in December: 2.95"
The wettest month (with the highest rainfall) is February (3.7").
The driest month (with the least rainfall) is July (0").
Average rainfall days in December
Saint Helena, CA
- Average rainfall days in December: 11.3 days
The month with the highest number of rainy days is March (13.5 days).
The month with the least rainy days is August (0.3 days).
Average snowfall in December
Saint Helena, CA
- Average snowfall in December: 0"
The month with the highest snowfall is March (0.04").
The months with the least snowfall are January, February, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in December
Saint Helena, CA
- Average snowfall days in December: 0 days
The month with the highest number of snowfall days is March (0.2 days).
The months with the least snowfall days are January, February, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in December /
Average sunshine in December
Saint Helena, CA
- Average daylight in December: 9h and 3min
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 30min).
- Average sunshine in December: 5h and 2min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days in December
Saint Helena, CA
- Average sunshine days in December: 19.1 days
The month with the most sunshine days is July (30 days).
The month with the least sunshine days is March (15.9 days).
Average UV index in December
Saint Helena, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Saint Helena, CA
- Average cloud cover in December: 42
The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility in December
Saint Helena, CA
- Average visibility in December: 6mi
The months with the highest visibility are February, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and March (5mi).
Saint Helena, California, USA
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