December weather forecast and climate
San Juan, PR

An old fort building and a yonder view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
An old fort building and a yonder view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront

What is the temperature in December in San Juan?

The average high-temperature, in December, in San Juan, is 83.8°F (28.8°C), while the average low-temperature is 73.4°F (23°C).
Average temperature in December - San Juan, PR
  • Average high temperature in December: 28.8°C

Warmest months (with the highest average high temperature) are August and September (31.8°C).
The month with the lowest average high temperature is January (28.4°C).

  • Average low temperature in December: 23°C

The month with the highest average low temperature is August (25.7°C).
Coldest months (with the lowest average low temperature) are January and February (22.2°C).

Average humidity in December - San Juan, PR
  • Average humidity in December: 74.7%

The month with the highest relative humidity is October (76.9%).
The month with the lowest relative humidity is March (71%).

Average rainfall in December - San Juan, PR
  • Average rainfall in December: 151mm

The wettest month (with the highest rainfall) is August (195mm).
The driest month (with the lowest rainfall) is March (79mm).

Average rainfall days in December - San Juan, PR
  • Average rainfall days in December: 19.6 days

Months with the highest number of rainy days are November and December (19.6 days).
The month with the lowest number of rainy days is March (12.2 days).

Average sea temperature in December - San Juan, PR
  • Average sea temperature in December: 27.7°C

The best month for swimming (with the highest average sea temperature) is September (29.4°C).
Coldest months (with the lowest average sea temperature) are February and March (26.1°C).

Average daylight in December / Average sunshine in December - San Juan, PR
  • Average daylight in December: 11h

The month with the longest days is June (Average daylight: 13.2h).
The month with shortest days is December (Average daylight: 11h).

  • Average sunshine in December: 7h

Months with most sunshine are March and July (Average sunshine: 9.1h).
The month with least sunshine is November (Average sunshine: 6.7h).

Average UV index in December - San Juan, PR
  • Average UV index in December: 8

Months with the highest UV index are March, April, May, June, July, August and September (UV index 12).
Months with the lowest UV index are January and December (UV index 8).

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