Since Puerto Rico has a tropical marine climate, it is relatively warm and sunny all year round. However, when it comes to the ‘coldest’ months of the year, you can expect January to have lows of around 70 degrees Fahrenheit. u003cbr/u003eu003cbr/u003eHowever, this month does still see some warmth, and the average highs throughout January reach around 83 degrees Fahrenheit.