Global Rainfall: How Much Falls Per Year?

Earth's average annual precipitation is ~1,000 mm (39 inches), but distribution is extremely uneven:

Wettest Places

• Mawsynram, India – 11,872 mm (467 in) – world record
• Cherrapunji, India – 11,777 mm
• Tutunendo, Colombia – ~11,770 mm

These equatorial zones get intense convectional rainfall from the Intertropical Convergence Zone (ITCZ) and orographic lift.

Driest Places

• Atacama Desert, Chile – <1 mm (0.04 in) – some weather stations have never recorded rain
• McMurdo Dry Valleys, Antarctica – 0 mm (katabatic winds evaporate all moisture)
• Arica, Chile – 0.76 mm

Key Drivers of Variation

• Latitude – Equatorial convergence vs. subtropical highs (deserts at ~30°)
• Topography – Windward slopes (wet) vs. rain shadows (dry)
• Prevailing Winds – Onshore flow brings moisture; offshore brings aridity
• Seasonality – Monsoons, Mediterranean wet/dry cycles

Climate change is intensifying extremes: wet regions get wetter, dry regions drier, and heavy rainfall events more frequent.