Antarctica: The Driest Continent on Earth

Antarctica receives an average annual precipitation of just 2 cm (0.79 inches) — almost entirely as snow. This makes it the driest continent (drier than the Sahara).

Why So Dry?

• Extreme Cold: Air at -40°C to -60°C holds almost no water vapor (saturation vapor pressure near zero).
• Katabatic Winds: Gravity-driven winds drain cold, dense air from the interior to coast, evaporating any moisture.
• Polar High Pressure: Persistent high-pressure system suppresses cloud formation.
• Distance from Moisture Sources: Surrounded by Southern Ocean, but cold air blocks evaporation; storms mostly circulate coast.

Regional Variation

• Interior (East Antarctic Plateau): < 2 cm/yr (e.g., Dome A, Vostok) — "polar desert".
• Coastal Areas: 20–60 cm/yr (still arid).
• Peninsula: Up to 100+ cm/yr (warmer, maritime influence).

Ice ≠ Wet

The massive ice sheet (avg 2.16 km thick, 90% of world's ice) accumulated over millions of years from minuscule annual snowfall that never melts. It's a frozen archive, not a wet place.