San Juan
Puerto Rico, USA
Long-term weather forecast
Long-term weather forecast

January weather forecast and climate
San Juan, PR

An old fort building and a view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
An old fort building and a view of the stunning San Juan city, Puerto Rico, with a clear view of the calm waterfront
January, like December, in San Juan, Puerto Rico, is another warm winter month, with average temperature ranging between max 83.1°F (28.4°C) and min 72°F (22.2°C).

Temperature

January is the coldest month, with an average high-temperature of 83.1°F (28.4°C) and an average low-temperature of 72°F (22.2°C).

Humidity

The average relative humidity in January is 74%.

Rainfall

In San Juan, during January, the rain falls for 17.6 days and regularly aggregates up to 4.6" (116mm) of precipitation. In San Juan, during the entire year, the rain falls for 198.5 days and collects up to 70.6" (1794mm) of precipitation.

Ocean temperature

In San Juan, the average seawater temperature is 79.7°F (26.5°C). Water temperature between 77°F (25°C) and 84.2°F (29°C) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

The average length of the day in San Juan is 11.2h.

Sunshine

In San Juan, the average sunshine in January is 7.7h.

UV index

Months with the lowest UV index are January and December, with an average maximum UV index of 8. A UV Index estimate of 8 to 10 represents a very high health vulnerability from unprotected exposure to the Sun's UV rays for ordinary individuals.
In January, the average maximum UV index of 8 translate into the following recommendations:
Take special precautions, as unprotected eyes and skin can be burned and damaged quickly. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.

What is the coldest month in San Juan?

January is the coldest month in San Juan, Puerto Rico, with an average high-temperature of 83.1°F (28.4°C) and an average low-temperature of 72°F (22.2°C).

What is the temperature in January in San Juan?

The average high-temperature, in January, in San Juan, is 83.1°F (28.4°C), while the average low-temperature is 72°F (22.2°C).

What is the average humidity in January in San Juan?

The average relative humidity in January is 74%.

How much does it rain in San Juan in January?

In January, in San Juan, the rain falls for 17.6 days. Throughout January, 4.6" (116mm) of precipitation is accumulated.

How warm is the water in January in San Juan?

In January, the average ocean temperature in San Juan is 79.7°F (26.5°C). For any water activity, surface water temperatures between 77°F (25°C) and 84.2°F (29°C) are considered as excellent and extremely pleasant for lengthened periods.

How many hours of daylight does San Juan have in January?

In January, the average length of the day in San Juan, Puerto Rico, is 11.2h.

How many hours of sunshine does San Juan have in January?

The average sunshine in January is 7.7h.

What are the months with the lowest UV index in San Juan?

Months with the lowest UV index in San Juan are January and December, with an average maximum UV index of 8.

How high is the UV index in January in San Juan?

In San Juan, Puerto Rico, the average daily maximum UV index in January is 8. A UV Index estimate of 8 to 10 represents a very high hazard to health from the exposure to the Sun's UV rays.
Average temperature in January - San Juan, PR
  • Average high temperature in January: 28.4°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 January: 22.2°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 January - San Juan, PR
  • Average humidity in January: 74%

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

Average rainfall in January - San Juan, PR
  • Average rainfall in January: 116mm

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

Average rainfall days in January - San Juan, PR
  • Average rainfall days in January: 17.6 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 January - San Juan, PR
  • Average sea temperature in January: 26.5°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 January / Average sunshine in January - San Juan, PR
  • Average daylight in January: 11.2h

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 January: 7.7h

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 January - San Juan, PR
  • Average UV index in January: 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).