Aerodrome observations: METAR, SPECI, AUTO

A METAR is the routine aerodrome weather observation, taken every hour on the hour. A SPECI is a special observation, same format, issued between the hourly METARs when conditions cross set criteria.

• METAR: hourly, at over 200 Canadian aerodromes. Not every station reports 24 hours a day, so check the CFS for the observing schedule.
• SPECI: triggered by a significant change (falling visibility or ceiling, a thunderstorm starting or ending), not by the clock.
• METAR AUTO / AWOS: an automatic station. One outside the lightning-detection network cannot report thunderstorms or lightning.
• RVR is added when it is 6,000 ft or less for the runway in use and/or the visibility is 1 SM or less.

Trap: a SPECI is an observation, not a forecast, and it fires on a change in conditions, not at a fixed time.

Practice