Puerto Rico had 3,808,610 inhabitants, an increase of about 8.1 % over the 1990 figure of 3,522,037. The population estimate for 2001 was 3,937,316. The average population density in 2001 was 439 persons per sq km ,a higher density than for any state.It has a distinct dry season. The mean annual temperature at San Juan, in the north, is 27°C, and the city receives an average of 1,330 mm of precipitation each year.The recorded temperature in the commonwealth has ranged from 4°C in 1911 at Aibonito to 39°C in 1906 at San Lorenzo. Puerto Rico is sometimes struck by damaging hurricanes traveling from the east, particularly from August to October.