Understand METAR, TAF and arrival weather
Understand the difference between weather observed now and the forecast window around your landing time.
A destination can be foggy now and clear by the time you land. BadWx uses both current weather reports and forecasts to help you choose a simulator flight with a challenging arrival.
METAR: an observation at the airport
A METAR reports observed airport weather, including wind, visibility, cloud layers and weather phenomena. In BadWx, observations give context for departure and destination conditions. Check the observation time: a report describes conditions at that time, not at your later arrival.
TAF: a forecast with time windows
A TAF describes expected airport weather over a forecast period. Conditions can change within that period. BadWx checks the forecast periods covering your estimated arrival rather than flagging a destination just because bad weather appears somewhere in its TAF.
Temporary (TEMPO) and probability (PROB) groups are included by default. Their conditions need not last throughout the window or occur at your exact landing time. An improving prevailing forecast can remove a match, although an overlapping adverse TEMPO or PROB group can still qualify.
The Aviation Weather Center's METAR and TAF reference explains the report formats and forecast change groups.
Why the arrival estimate matters
The estimate combines airport-to-airport distance, aircraft cruise speed, a wind adjustment, a climb and descent allowance, and the configured preflight allowance. The wind adjustment uses surface winds as an approximation; it does not model winds along your full flight route.
Flight time excludes preflight; the arrival clock includes it. The clock can show UTC or destination local time, but the adverse forecast windows in Details are shown in UTC (Z). Use UTC when comparing those times.
For example, low visibility forecast from 14:00 to 16:00 UTC could match an estimated arrival at 15:00 but not 17:00. BadWx checks the central arrival estimate, not whether its entire uncertainty range fits inside that window. These times are illustrative, not a live forecast.
Read the scores alongside the weather details
- Severity
- A relative 1–10 score combining departure and arrival weather flags. Low visibility or low cloud also adds weight when arrival is at night. It is not a runway-specific approach rating.
- Arrival Match
- A score based on your position within a forecast window, the weather flags and how far ahead arrival is. Its percentage is not a calibrated probability, a TAF's PROB value or the separate Severity score.
- Arrival uncertainty
- A rough timing range, not a statistical confidence interval. Arriving earlier or later can move you outside the adverse forecast window.
Useful weather terms in the planner
BadWx's ceiling check uses the lowest broken (BKN) or overcast (OVC) cloud base, in feet above the airport. Its visibility threshold is in statute miles, and wind and gusts are in knots. Raw international reports can use different visibility units; read the report format when comparing values.
Check freshness before choosing a flight
The last-updated badge reflects the most recent airport weather fetch in the cache. It does not mean every airport's reports were issued then. Open Details → METAR / TAF and check the METAR observation time, TAF issue time and forecast validity.
Current observation values can differ from the arrival forecast. Use the TAF period covering your planned landing, and check again if preparation or the SimBrief plan changes your timing. MSFS live weather may also differ from the reports.
Ready to use these details? Follow the MSFS weather-flight guide or learn how to send a route to SimBrief.