Why Are Deserts So Hot During the Day (and Cold at Night)?

The Extreme Swings

The Sahara Desert can reach 50°C during the day and plummet to 5°C at night — a swing of 45 degrees in just 12 hours. No other environment on Earth experiences such dramatic daily temperature changes.

Why Deserts Get So Hot

1. No cloud cover: Clear skies let solar radiation reach the ground unfiltered
2. Dry air: Without moisture to absorb and scatter sunlight, more energy reaches the surface
3. Low vegetation: Plants cool the air through transpiration; desert soil absorbs and re-radiates heat
4. Sand and rock: These materials heat up quickly under direct sun

Why Deserts Get So Cold at Night

The same factors that make deserts hot during the day make them cold at night:

1. No clouds: Nothing to trap the day's heat — it radiates straight into space
2. Dry air: Water vapour is a greenhouse gas; without it, heat escapes rapidly
3. Sand cools quickly: It has low thermal capacity and loses heat fast

Desert Temperature Records

Humid vs Dry Heat

This is why "it's a dry heat" matters. At 40°C with 10% humidity (desert), your sweat evaporates instantly, cooling you effectively. At 40°C with 80% humidity (tropical), sweat cannot evaporate, making it far more dangerous.

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Compare desert and tropical forecasts on Weather Tomorrow.