Reading the Sky: Cloud Types

Introduction

The sky is an instrument

Clouds are not just weather decoration — they are a free, real-time readout of atmospheric conditions. With a few minutes of observation, you can forecast the next few hours of weather with surprising accuracy.

A cloud forms when rising, moist air cools below its dew point — the temperature at which water vapour condenses into tiny liquid droplets or ice crystals around microscopic particles called condensation nuclei. The type of cloud that forms depends on how fast the air rises, how moist it is, and at what altitude condensation occurs.

Modern cloud classification descends from British pharmacist Luke Howard, who proposed the Latin-based naming system in 1803. Today the World Meteorological Organization's International Cloud Atlas is the global standard.

Clouds are classified by two properties: altitude (how high they form) and shape (puffy, layered, or wispy).

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