ΔT

Δt is the time difference between Universal Time, a time scale based on the Earth's non-uniform rotation, and Terrestrial Time, a uniform time scale currently based on the caesium atomic clock.

Δt and Δt may also refer to:

The term is used to represent other time differences:

Δt, a difference in time, may refer to

• The interval of time used in determining velocity.
• The increment between successive nerve impulses.

The term is also used to represent differences or changes of temperature:

Δt, a difference in temperature, may refer to

• In discussions of climate change.
• In discussions of heat transfer.
• In discussions of the effects of thermal gradients.