San Juan has a tropical monsoon climate (Am) and has an average temperature of  although  or higher temperatures are seen on an average 79 days annually, more commonly occurring during the wetter months of the northern summer, especially if the winds come from the south. In the winter, temperatures can drop to around , though the average winter low is . The coolest temperature officially recorded was  on March 3, 1957, and the hottest was  on October 9, 1981; the record cold daily maximum is  on February 4, 1935, while the record warm daily minimum is  on August 11, 1995, the most recent of four occasions. With a mean minimum of 67 °F (19 C), San Juan is in USDA plant hardiness zone 13B the highest category. Rainfall is well-distributed throughout the year, but the months of January, February, and March are the driest; as March averages just  of rain, the city falls under the tropical monsoon category. Rainfall averages , falling on an average 198.5 days per year; despite this dampness, the city averages 2,970 hours of sunshine per year, or just over ⅔ of the possible total. Annual rainfall has historically ranged from  in 1991 to  in 2010.