Chile (Atacama)

Chile (Atacama) – What you should know

The Atacama in northern Chile is among the driest deserts on Earth, and the station shows it: from April to November only a few millimetres fall on average, at times less than 1 mm (< 0.1 in) a month. Most trips are based in San Pedro de Atacama at around 2,400 m (7,874 ft). The air is extremely dry (around 12–16% humidity in late winter and spring), the sun shines ten to thirteen hours a day on average, and the UV index peaks around 10 in October and November.

The difference between day and night temperatures is large. In high summer daytime highs average 25–26°C (77–79°F) and nights around 12°C (54°F); in winter highs average 19°C (66°F), nights around 3°C (37°F), and on the coldest nights from June to August just below 0°C (32°F). Excursions to the El Tatio geysers at around 4,300 m (14,108 ft) start before sunrise and are much colder than in town. Because of the altitude, many people find breathing hard at first; a day or two of acclimatisation and plenty of water help.

January and February are the time of the so-called Altiplanic winter: thunderstorms from the east bring around 47 mm (1.9 in) on five rain days in February, can close roads and cancel tours. Anyone wanting fixed programmes therefore does better to travel in October and November or in March. For stars the Atacama, with clear, dry air and almost no light pollution, is one of the best destinations; nights are darkest around new moon.