Astroclimatology of Paranal

Cloudiness at Paranal

(Source: Paranal Night Reports and La Silla Team Reports)
A photometric night calls for 6 hours of consecutive photometric night time. The sky is photometric when no clouds are higher than 5 degrees above the horizon. Nighttime is when the sun has an altitude lower than 18 degree below the horizon.

Cloudiness Monthly Averages Graph and Data (1983-now)

Cloudiness differential Paranal-La Silla (1983-now)

Cloudiness seasonal distribution (1987-1995), (1983-2001), (1983-now).

Cloudiness yearly variations (1984-now).

Relationship to El-Nino : (The ESO Messenger 90, December 97)