METAR & TAF

What is a METAR?

A METAR (Meteorological Aerodrome Report) is an hourly surface weather observation taken at airports. It is the most authoritative single-point surface observation available — used by pilots worldwide to assess conditions before flight.

Wind

Reported in knots from true north. Gusts are brief peaks above the sustained speed. Calm = winds under 3 knots. Variable (VRB) means direction is inconsistent, common in light winds.

Visibility

Reported in statute miles. 10+ SM = unrestricted. Below 3 SM = IFR conditions requiring instruments. Below 1 SM = very poor visibility, likely dense fog or heavy precipitation.

Sky / Ceiling

FEW = 1–2 oktas covered · SCT = 3–4 oktas · BKN = 5–7 oktas (ceiling) · OVC = 8 oktas (overcast). Heights in feet AGL. The ceiling is the lowest BKN or OVC layer — what limits cloud bases.

Altimeter Setting

Barometric pressure adjusted to sea level in inches of mercury. Standard atmosphere = 29.92 inHg. Pilots set this in their altimeters to read correct altitude. Rising = improving; falling rapidly = storm approaching.

TAF Forecast

Terminal Aerodrome Forecast — a 24–30 hour aviation forecast issued by NWS. TEMPO = temporary conditions lasting under an hour. BECMG = gradual change expected. PROB30/40 = 30%/40% probability of conditions.