User Guide›Density altitude alert

Density altitude alert

An orange banner appears on the METAR only when the estimated density altitude at your facility's elevation is 3,000 ft or higher.

High density altitude reduces engine and rotor performance, and matters most on hot days and at higher-elevation sites. TAFs carry neither temperature nor pressure, so this alert is METAR-only.

The value is computed from the reporting station's temperature and altimeter setting applied to your facility's field elevation (not the station's), using the standard pressure-altitude and ISA-deviation method: pressure altitude from the altimeter, then adjusted for how far the temperature departs from standard.

Confirm against your flight manual Because temperature and pressure come from the nearest station — which may be some distance away — treat the figure as a planning estimate, and always confirm performance against your rotorcraft flight manual.

Related heat cue on the raw report: Temperature alert. How station distance weakens any station-derived figure: Station distance.