Mexico City has a subtropical highland climate, with warm summers and mild winters, and an annual average temperature of 64°F (18°C). Seasonal variations in temperature are small, but May is the warmest month of the year, and January the coldest, when night frosts are possible. The average maximum temperatures of late spring and summer may reach up to 77°F (25°C), and the average low winter temperatures reach 45°F (7°C). Mexico City has a high average annual rainfall, with the wettest month being July, and the driest month February. Even during the summer rainy season, travellers are likely to get plenty of sunshine between showers. Mexico City suffers from terrible air pollution and the city is often smoggy, with poor visibility. This air pollution is at its worst during winter. The city is a year-round travel destination, but the best time to visit Mexico City is in the spring months of April and May.
