AIRMET

An AIRMET is a weather advisory issued to inform pilots of moderate or potentially hazardous weather conditions that may affect the safety of flight — particularly for light aircraft and VFR operations. AIRMETs cover less severe conditions than SIGMETs, but they are still operationally significant.

AIRMETs are especially useful for general aviation, training flights, and low-level VFR traffic.

• Warn pilots of weather conditions that may impact flight safety
• Support decision-making during flight planning and in-flight updates
• Assist ATC and FIS in advising aircraft operating in affected areas
• Complement SIGMETs, which cover more severe phenomena

AIRMETs are usually structured similarly to SIGMETs but may vary by national meteorological authority. A typical AIRMET includes:

• Issuing center and region (FIR)
• Valid time period (usually 4–6 hours)
• Description of weather phenomenon
• Altitude/flight level range
• Area of coverage
• Intensity and trend (e.g., intensifying, weakening)

Example:
AIRMET SIERRA VALID 081000/081400
FOR AUSTRIA FIR
MTN OBSC DUE TO CLDS AND FOG
TOPS FL080
MOV E 25KT

Translation:

• AIRMET SIERRA (mountain obscuration)
• Valid from 10:00 to 14:00 UTC
• For Austria FIR
• Mountain obscuration due to clouds and fog
• Cloud tops up to FL080
• Weather moving east at 25 knots

• Preflight briefing systems
• National meteorological service websites (e.g., Austro Control, DWD)
• AIP and NOTAM briefings
• VOLMET and ATIS (select advisories)
• Flight Information Services (FIS) enroute

• “AIRMET in effect for widespread fog below 1000 feet, advise if deviating”
• “Wien Information, OE-XYZ, request update on icing AIRMET in Salzburg sector”

• ✅ Always check AIRMETs during preflight planning, especially for VFR
• ✅ Be cautious when flying near mountainous terrain or in winter weather
• ✅ Use LearnATC to practice diversion decisions and weather avoidance based on AIRMETs
• ✅ If conditions worsen, be ready to request IFR clearance or alternate routing