How much of the movement of clouds is due to Earth’s rotation?

On a still day, clouds move slowly across the sky. How much of this is due to Earth’s rotation? Do clouds seem to move faster at the equator?

Peter Bursztyn, Barrie, Ontario, Canada

Clouds move in response to the local winds. Although the air immediately around you may be still, the winds are far stronger thousands of metres higher up. That is why clouds are usually in motion, even on apparently windless days. But part of a cloud’s motion is indeed governed by Earth’s rotation.

Strong solar heating at the equator causes the air above it to expand, forming a…