There is a rainy season and a dry season in Peru. November to April is the rainy season, and so many people choose to visit Machu Picchu before or after this period.
Machu Picchu site and trails are closed for clean up during February. See When to visit Machu Picchu for more comprehensive information on when to visit.
AD: Top Rated Inca Trail, Lares Trail, Machu Picchu, Lake Titicaca, Rainforest Tours