The weather in Peru is changeable, and it all depends on where you are. Peru has different natural regions: the coast, the mountains and the jungle.
Coast: On the north coast and on the desert areas, the weather is warm and sunny throughout the year. On the central coast is the same during the summer (from December to March), and in winter (June to September) is wet and cloudy most of the time.
Mountain: The rainy season begins in October and ends in March, and from April until September, the weather is usually dry. In June, July and August there are frosts, where the temperature drops considerably, especially very early in the morning, and during the night. However, the sun usually shines throughout most of the year.
Jungle: The Peruvian jungle is usually tropical and humid during most of the year, being the rainy season from November to March, and it is drier from April to October. Temperatures are likely to fall by days, between May and August.