Term

thermal

Daniel MarkFounder & Editor, Aviatopia
Published Mar 1, 2026Updated Mar 1, 20261 min read

A column of rising warm air generated by uneven surface heating — used by glider pilots for lift and a source of convective turbulence for powered aircraft.

aviation-glossary

Quick Facts

Type
Atmospheric Phenomenon
Definition
A column of rising warm air generated by uneven surface heating
Used By
Pilots

Definition#

A thermal is a column or bubble of rising air produced by differential surface heating. Darker surfaces (parking lots, plowed fields) heat air more than surrounding areas, creating localized updrafts.

Why It Matters Operationally#

Thermals are the primary lift source for glider and sailplane operations. For powered aircraft, thermals cause convective turbulence, especially in the afternoon over land. Strong thermals can develop into cumulus and eventually cumulonimbus clouds.

See Also

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