Oaxaca City lies in a valley at an altitude of 5,000 feet above sea level, and is surrounded by mountain ranges. The city's easygoing atmosphere is complemented by year-round spring temperatures, although days can get quite hot even in winter. Evenings can be chilly, so make sure to bring a light jacket. The rainy season runs from July to October, with September being the wettest month. Generally you can count on clear mornings, with clouds and showers usually arriving in the late afternoon. The Oaxacan coast lies well within the tropics, so it's always hot and often humid.