How the Monsoon Works

In early November 2026 Thailand was still waiting for its cool season to be declared, as high pressure from China began to push south. This film explains the monsoon behind that wait: why land and sea heat up at different rates, how a sea breeze grows into a seasonal wind the size of a continent, how the tropical rain belt follows the Sun and the Earth's spin turns the winds, why Thailand has a rainy season and a cool season, how mountains squeeze out record rains in India, why southern Thailand's east coast is wettest in November, and how sailors and scientists came to understand it.

Waiting for the cool wind

What decides when Thailand’s winter arrives.

A wind with seasons

What “monsoon” means.

Hot sand, cool sea

Why land and water warm at different speeds.

A breeze the size of a continent

From day and night to summer and winter.

A rain belt that follows the Sun

The Intertropical Convergence Zone.

The spin that bends the wind

Why the rainy-season wind comes from the southwest.

Thailand’s rainy season

From mid-May to mid-October.

Mountains wring out the clouds

Orographic rain and the rain shadow.

The wettest places on Earth

Northeast India.

India’s great rains

Three quarters of the year’s rain in four months.

The cool wind

The northeast monsoon, and what makes winter official.

The south gets the rain

Why November is wettest on the southern east coast.

Riding the wind

From sailors’ knowledge to science.

The wind that changes sides

Timeline and sources.

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