In meteorology and aviation, terminal aerodrome forecast (TAF) is a format for reporting weather forecast information, particularly as it relates to aviation. TAFs are issued every six hours for major civil airfields: 0000,0600,1200,1800 UTC, and generally apply to a 24 or 30-hour period, and an area within approximately five statute miles (or 5NM in Canada) from the center of an airport runway complex.