How to Read and Interpret TAF Terminal Aerodrome Forecasts

Published on March 20, 2026 8 min FOX SIM Editorial Team

A TAF (Terminal Aerodrome Forecast) is the official weather forecast established for a 5-statute-mile radius around an airport over a 24 to 30-hour period. Its practical value lies in constructing a clean flight timeline for destination and alternate requirements.

Validity Period & Base Conditions

The TAF header displays the ICAO airport identifier, issuance time, and valid forecast period (e.g., 2812/2918 indicating validity from day 28 at 1200Z to day 29 at 1800Z).

The initial lines describe base conditions expected to prevail until subsequent change groups take effect.

Understanding Change Groups: FM, BECMG, TEMPO & PROB

FM (From) indicates a rapid, permanent shift starting at the specified hour and minute (e.g., FM281600). All preceding weather lines are superseded.

BECMG (Becoming) indicates a gradual transition occurring over an interval. TEMPO denotes transient fluctuations lasting less than one hour per instance. PROB30/PROB40 reflects probability of thunderstorms or precipitation.

Nota Educacional

Este artigo faz parte da biblioteca educacional FOX SIM e destina-se a fins de estudo e simulação de voo. Para operações aeronáuticas reais, consulte sempre as publicações oficiais (AIP, ROTAER, NOTAM) e manuais aprovados da aeronave.

All articles