Peru has three climate zones, one of which governs the coastal region. Its desert landscape is caused by the cold Humboldt Current, which prevents cloud formation over the land. Lima is generally sunny and humid, with next to no rainfall, though it experiences heavy sea mists from April to November. The northern coast has hot, sunny summers, with occasional rain showers. The coast gets less arid farther north, as the effect of the Humboldt Current decreases.The Andes region is cool, and its wet season runs from October to April. Its dry season lasts from May to September. During the dry season, days in the highlands are clear and sunny, though nights become very cold - especially at altitude.The forested region of the Amazon Basin has an equatorial climate, where conditions involve hot weather and frequent rain throughout the year.The peak tourist season runs from May to October, particularly in July and August. Winter (June to September) is the best time to walk the Inca Trail, given the wonderful visibility travellers can expect during the clear, sunny days. This is also a good time to visit the jungle basin, as there are fewer mosquitoes.