The two most common elements of climate for which Mykonos is famous are sunshine and wind. Rainfall is infrequent, generally falling between the months of February and March, allowing the sun to shine for as many as three hundred days of the year. Because of this arid condition natural vegetation is limited. During the summer months the temperature may occasionally reach the upper 30's but due to the cooling factor of the frequent winds an average of 28'C can be expected. Winters on the island are mild with an average temperature of 15 degrees. It is only on very rare occasions the thermometer may reach freezing. Due to the moderating influence of the surrounding sea the island's temperatures are usually 2 degrees warmer in the winter and 2 degrees cooler in the summer than mainland Athens. This condition directly effects the cycle of both domestic and wild vegetation as the growing season occurs from the beginning of winter and ends in mid summer. Of the winds that effect the island two kinds are most common. During the winter months heavy winds from the south arrive and often bring with them electrical storms. Of these the most famous wind is the "Sirocco" which every spring brings sand from the deserts that boarder the Mediterranean in the form of red rain. As the season heads toward summer the north wind takes over and with various degrees of strength, blows daily. The most notable of these winds is the "Meltami" that during July and August will blow steady throughout the day and then reduce its velocity during the night. Gale-force winds are not uncommon.