Although the Seychelles Islands lie close to the equator, their maritime situation results in coastal temperatures that are fairly constant at about 27° C (81° F ) throughout the year. At higher altitudes, temperatures are lower, especially at night. Mean annual rainfall at sea level on Mahé is 236 cm (93 in); in the mountains there may be as much as 356 cm (140 in) a year. On the southwestern coral islands, rainfall is much lower, averaging about 50 cm (20 in) a year on Aldabra. May to October is the relatively dry sunny season; in this period, the southeast monsoon winds bring brief showers every two or three days. The northwest monsoon arrives in December and continues until March, bringing frequent and heavy rain. Humidity is high, especially in the coastal areas.