December weather forecast
Key Biscayne, FL

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The beautiful and dramatic landscape of the Miami Crandon Park in Key Biscayne, Florida
The beautiful and dramatic landscape of the Miami Crandon Park in Key Biscayne, Florida

Weather in December

The first month of the winter, December, is also a moderately hot month in Key Biscayne, Florida, with an average temperature ranging between min 69.4°F (20.8°C) and max 75.7°F (24.3°C).

Temperature

The transition from November to December sees average high-temperatures adjusting to a still warm 75.7°F (24.3°C), from a not significantly different 77.9°F (25.5°C). Key Biscayne maintains an average of approximately an agreeable 69.4°F (20.8°C) during December nights, with only a minimal decrease from the daytime temperature.

Humidity

The most humid month is December, with an average relative humidity of 75%.

Rainfall

In Key Biscayne, in December, during 11.7 rainfall days, 0.75" (19mm) of precipitation is typically accumulated. In Key Biscayne, during the entire year, the rain falls for 182.7 days and collects up to 16.38" (416mm) of precipitation.

Ocean temperature

In December, the average ocean temperature is 76.5°F (24.7°C).
Note: Every individual's cold threshold differs, but factors like today's sunshine, wind, and temperature can tip the scales for a delightful swim in 76.5°F (24.7°C) waters. For reference, Olympians swim in waters of 77°F (25°C) to 82.4°F (28°C).

Daylight

With an average of 10h and 36min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 6:50 am and sunset at 5:29 pm. On the last day of December, sunrise is at 7:06 am and sunset at 5:40 pm EST.

Sunshine

December has the least sunshine of the year, with an average of 6.4h of sunshine.

UV index

January and December, with an average maximum UV index of 5, are months with the lowest UV index in Key Biscayne, Florida. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: A maximum UV index of 5 in December translates into the following recommendations:
Prioritize safety - Recommendations to avert sunburn are shared. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Always opt for UVA and UVB-resistant sunglasses on radiant days. Beware! Reflections from sand and water can intensify the Sun's UV radiation.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average December temperature in Key Biscayne?

The high-temperature in Key Biscayne, Florida, during December is 75.7°F (24.3°C) and the low-temperature is 69.4°F (20.8°C). In October, the average heat index (a.k.a. 'feels like', 'real feel'), which represents the influence of relative humidity on air temperature, is estimated at 89.6°F (32°C).

What is the most humid month in Key Biscayne?

With an average relative humidity of 75%, December is the most humid month in Key Biscayne, Florida.

What is the average humidity in December in Key Biscayne?

The average relative humidity in December in Key Biscayne, Florida, is 75%.

How many days does it rain in December in Key Biscayne?

In December, in Key Biscayne, the rain falls for 11.7 days. Throughout December, 0.75" (19mm) of precipitation is accumulated.

How warm is the water in December in Key Biscayne?

In Key Biscayne, in December, the average water temperature is 76.5°F (24.7°C). Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 76.5°F (24.7°C) water may be enjoyable.

What is the month with the shortest days in Key Biscayne?

The month with the shortest days in Key Biscayne is December, with an average of 10h and 36min of daylight.

How many hours of daylight does Key Biscayne have in December?

In December, the average day length in Key Biscayne, Florida, is 10h and 34min.

When is the sunrise / sunset in December in Key Biscayne?

On the first day of December in Key Biscayne, Florida, sunrise is at 6:50 am and sunset at 5:29 pm. On the last day of the month, sunrise is at 7:06 am and sunset at 5:40 pm EST.

What is the month with the least sunshine in Key Biscayne?

The month with the least sunshine in Key Biscayne is December, with an average of 6.4h of sunshine.

How long on average sun shines in December in Key Biscayne?

In December, the average sunshine duration in Key Biscayne, Florida, is 6.4h.

What are the months with the lowest UV index in Key Biscayne?

The months with the lowest UV index are January and December, with an average maximum UV index of 5.

How high is the UV index in December in Key Biscayne?

In December, the average daily maximum UV index in Key Biscayne is 5. A UV Index of 3 to 5 symbolizes a moderate health threat from unprotected exposure to UV radiation.

Average temperature in December
Key Biscayne, FL

Average temperature in December - Key Biscayne, FL
  • Average high temperature in December: 75.7°F

The warmest month (with the highest average high temperature) is August (87.1°F).
The month with the lowest average high temperature is January (73°F).

  • Average low temperature in December: 69.4°F

The month with the highest average low temperature is August (82.6°F).
The coldest month (with the lowest average low temperature) is January (65.1°F).

Average pressure in December
Key Biscayne, FL

Average pressure in December - Key Biscayne, FL
  • Average pressure in December: 30.08"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are September and October (29.95"Hg).

Average wind speed in December
Key Biscayne, FL

Average wind speed in December - Key Biscayne, FL
  • Average wind speed in December: 11.1mph

The windiest month (with the highest average wind speed) is March (11.6mph).
The calmest month (with the lowest average wind speed) is July (8.1mph).

Average humidity in December
Key Biscayne, FL

Average humidity in December - Key Biscayne, FL
  • Average humidity in December: 75%

The month with the highest relative humidity is December (75%).
The month with the lowest relative humidity is March (70%).

Average rainfall in December
Key Biscayne, FL

Average rainfall in December - Key Biscayne, FL
  • Average rainfall in December: 0.75"

The wettest month (with the highest rainfall) is August (2.8").
The driest month (with the least rainfall) is January (0.43").

Average rainfall days in December
Key Biscayne, FL

Average rainfall days in December - Key Biscayne, FL
  • Average rainfall days in December: 11.7 days

The month with the highest number of rainy days is September (24.5 days).
The month with the least rainy days is February (8.7 days).

Average sea temperature in December
Key Biscayne, FL

Average sea temperature in December - Key Biscayne, FL
  • Average sea temperature in December: 76.4°F

The best month for swimming (with the highest average sea temperature) is August (86.5°F).
The coldest month (with the lowest average sea temperature) is February (74°F).

Average daylight in December /
Average sunshine in December
Key Biscayne, FL

Average daylight in December / Average sunshine in December - Key Biscayne, FL
  • Average daylight in December: 10h and 4min

The month with the longest days is June (Average daylight: 13h and 42min).
The month with the shortest days is December (Average daylight: 10h and 36min).

  • Average sunshine in December: 6h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 24min).

Average sunshine days in December
Key Biscayne, FL

Average sunshine days in December - Key Biscayne, FL
  • Average sunshine days in December: 14.5 days

The month with the most sunshine days is March (17 days).
The month with the least sunshine days is September (3.2 days).

Average UV index in December
Key Biscayne, FL

Average UV index in December - Key Biscayne, FL
  • Average UV index in December: 5

The months with the highest UV index are May, June, July, August, September and October (UV index 7).
The months with the lowest UV index are January and December (UV index 5).

Average cloud cover in December
Key Biscayne, FL

Average cloud cover in December - Key Biscayne, FL
  • Average cloud cover in December: 32

The month with the most cloud cover is October (Cloud cover 35).
The month with the least cloud cover is April (Cloud cover 26).

Average visibility in December
Key Biscayne, FL

Average visibility in December - Key Biscayne, FL
  • 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).

Key Biscayne, Florida, USA

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