The yearly precipitation varies from around 600 millimetres (23.6 in) in the lowland valleys to around 1,200 millimetres (47.2 in) in areas of the northern and eastern escarpment bordering South Africa.
Most of the rain falls as summer thunderstorms: 85% of the annual precipitation falls between the months of April and October. The winters—between May and September are usually very dry.
Snow is common in the deserts and low valleys between May and September; the higher peaks can experience occasionally significant snowfall year-round. Annual variance in rainfall is quite erratic, which leads to periodic droughts in the dry season (May to September) and flooding, which can be severe in the rainy season (October-April).