December weather forecastGrand Isle, LA
December
Weather in December
In December, the winter season's influence unmistakably enters Grand Isle’s weather, with the temperature tailing down to an annual low of 53.1°F (11.7°C). The city's cloud cover increases to a maximum 42%, concurring with the winter theme, reducing the influence of direct sunlight. The change in temperature is reflected in the sea, which records the lowest temperature, rendering water activities significantly less attractive. Amidst the cooling trend, the weather in December stands out from other months, exuding a calm and serene winter vibe.Temperature
The advent of December brings an average high-temperature of an enjoyable 64.9°F (18.3°C), almost identical to the preceding month. Throughout the nights in December, Grand Isle notes an average low of 56.7°F (13.7°C), a small dip from the daytime peak.Humidity
February and December, with an average relative humidity of 78%, are the most humid months.Rainfall
In Grand Isle, during December, the rain falls for 11.9 days and regularly aggregates up to 1.65" (42mm) of precipitation. Throughout the year, there are 151.9 rainfall days, and 22.01" (559mm) of precipitation is accumulated.Snowfall
In Grand Isle, snow does not fall in February through December.Ocean temperature
In Grand Isle, the average seawater temperature in December is 64.2°F (17.9°C).Note: For the majority, swimming in water with a temperature of 64.2°F (17.9°C) is not enjoyable. The difficulty in managing breathing rises as the temperature decreases from 69.8°F (21°C) to 59°F (15°C).
Daylight
December has the shortest days of the year, with an average of 10h and 18min of daylight.On the first day of the month, sunrise is at 6:37 am and sunset at 5:01 pm. On the last day of December, sunrise is at 6:53 am and sunset at 5:12 pm CST.
Sunshine
The month with the least sunshine is December, with an average of 5.4h of sunshine.UV index
January and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: A maximum high UV index of 4 in December translates into the following recommendations:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Grand Isle, LA
- Average high temperature in December: 64.9°F
The warmest months (with the highest average high temperature) are July and August (86.9°F).
The month with the lowest average high temperature is January (61.7°F).
- Average low temperature in December: 56.7°F
The month with the highest average low temperature is August (81.3°F).
The coldest month (with the lowest average low temperature) is January (53.1°F).
Average pressure in December
Grand Isle, LA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is September (29.96"Hg).
Average wind speed in December
Grand Isle, LA
- Average wind speed in December: 12.2mph
The windiest month (with the highest average wind speed) is January (12.4mph).
The calmest month (with the lowest average wind speed) is July (8mph).
Average humidity in December
Grand Isle, LA
- Average humidity in December: 78%
The months with the highest relative humidity are February and December (78%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Grand Isle, LA
- Average rainfall in December: 1.65"
The wettest month (with the highest rainfall) is August (4.72").
The driest months (with the least rainfall) are February and April (0.87").
Average rainfall days in December
Grand Isle, LA
- Average rainfall days in December: 11.9 days
The month with the highest number of rainy days is August (20.7 days).
The month with the least rainy days is November (7.5 days).
Average snowfall days in December
Grand Isle, LA
- Average snowfall days in December: 0 days
The month with the highest number of snowfall days is January (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October, November and December (0 days).
Average sea temperature in December
Grand Isle, LA
- Average sea temperature in December: 64.1°F
The best month for swimming (with the highest average sea temperature) is August (87.5°F).
The coldest month (with the lowest average sea temperature) is January (61.4°F).
Average daylight in December /
Average sunshine in December
Grand Isle, LA
- Average daylight in December: 10h and 18min
The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).
- Average sunshine in December: 5h and 24min
The month with the most sunshine is June (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 24min).
Average sunshine days in December
Grand Isle, LA
- Average sunshine days in December: 16.3 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is August (6.5 days).
Average UV index in December
Grand Isle, LA
- Average UV index in December: 4
The months with the highest UV index are May, June, July, August and September (UV index 7).
The months with the lowest UV index are January and December (UV index 4).
Average cloud cover in December
Grand Isle, LA
- Average cloud cover in December: 42
The month with the most cloud cover is December (Cloud cover 42).
The month with the least cloud cover is May (Cloud cover 23).
Average visibility in December
Grand Isle, LA
- 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).
