Plain English Meaning

TEMPO marks a short-lived change in the weather forecast. The conditions listed after it are expected to come and go briefly during the stated time window, not to last the whole period.

Full Definition

A change indicator used in a Terminal Aerodrome Forecast (TAF) to show that the forecast conditions following it are expected to occur for periods of less than one hour at a time, and in total are not expected to cover more than half of the time period that follows the indicator. The TEMPO group is followed by a beginning and ending time, and the conditions inside the group are temporary fluctuations within that window — not the prevailing weather.

Context Anchor

Seen in airport weather forecasts when conditions such as visibility, ceiling, wind, or precipitation may change for short periods.

Derivation

TEMPO is shortened from temporary, from the Latin tempus meaning time. The use keeps that meaning — something tied to a stretch of time rather than the steady, prevailing .