The average annual rainfall is around , of which over three-quarters falls from November to March. Between May and September, rainfall is extremely rare: the median rainfall is zero in August, less than in July and September and less than in April, May, June and October. Variability is extreme, however, and totals as high as occur roughly one year in ten, whilst in the driest years as little as can be recorded. Between December and March, monthly totals can exceed if the monsoon is vigorous, with the wettest month being January 1984 with .