Pisco sits in one of the driest regions on earth — it almost never rains, which means there is no bad season in the conventional sense. The main variable is cloud cover and temperature. From December to April, a thick coastal fog called the garúa rolls in from the Pacific, bringing grey skies but mild temperatures of around 18–24°C. This is also the main tourist season.
From June to November the fog lifts, skies are clearer, and the sun is stronger, but temperatures drop slightly and the sea is noticeably colder. The Humboldt Current keeps the water cold year-round — swimming in the ocean is for the hardy, and most visitors are here for the wildlife rather than the beach. Boat tours to the Islas Ballestas run year-round, weather permitting.