Definition
In a METAR, DU is the contraction used to report widespread dust suspended in the air, reducing visibility. It is reported when fine particles of earth or sand have been lifted into the atmosphere and remain suspended over a broad area, rather than being raised in a localized gust or storm.
Plain English
DU on a weather report means the air has dust floating in it across a wide area, and that dust is making it harder to see.
Context Anchor
Seen in the present weather section of a METAR, especially in dry or windy areas.
Derivation
DU is simply a two-letter contraction of the English word dust, chosen by international weather coding convention. METAR codes use short letter pairs so reports stay compact and readable across languages.
Why Pilots Care
Dust reduces visibility and can affect takeoff, landing, and flight safety in arid areas.
Intuition Check
Do not read DU as ordinary dirt or dust sitting on a surface. In a METAR, DU means dust suspended in the air as a reported weather condition.
Example Sentence 1
The METAR included DU in the present weather group, with visibility reported at three statute miles.
Example Sentence 2
Pilots review the METAR for DU before departing from desert airports where strong winds lift dust into the air.