The best time to travel in the highlands is during the dry season, (April to October), this is the cooler winter period. In the southern altiplano the sky will be blue but it will be very cold, dropping to many degrees below freezing at night. For most trips the dry season is best because the weather is stable and the roads are in good condition. The summer rainy season from November to March can cause transport problems in the highlands, while the eastern lowlands are warm and steamy year-round. Depending on your activity and region you are traveling to, weather, road or river conditions may warrant travel only during certain seasons.