How do I read a METAR for flight simulation?

To read a METAR for flight simulation, scan it left to right: station, time, wind, visibility, weather, cloud, temperature/dew point and pressure. Then turn those groups into decisions: runway, altimeter setting, VFR or IFR, crosswind and icing risk, and whether the simulator's live weather is plausible.

What is a METAR in flight simulation?

For our Aviation & Real-World Flying coverage, a METAR is a coded surface weather observation for an aerodrome. We use it to check live weather, create a manual weather preset, brief a departure or approach, and decide whether a planned VFR flight still makes sense.

The main report describes conditions at the observation time, not what will happen later. An appended trend such as NOSIG adds a short outlook, but use the relevant TAF when you need a fuller aerodrome forecast.

How do you decode a METAR?

Read every METAR in the same sequence, while allowing for optional groups such as runway visual range and remarks. Take this illustrative report:

EGLL 121350Z 24012KT 9999 SCT020 BKN035 18/12 Q1016 NOSIG

1. Station: EGLL identifies London Heathrow. Check this first because a nearby station may have different wind, visibility and cloud.
2. Observation time: 121350Z means the 12th day of the month at 13:50 UTC. The code does not state the month or year; those come from the report context. Fast-changing weather can make even a fairly recent observation unrepresentative.
3. Wind: 24012KT means wind from 240 degrees true at 12 knots. Gusts appear as 24012G22KT, calm as 00000KT, and some countries use metres per second rather than knots.
4. Visibility: 9999 means 10 km or more, not unlimited visibility. ICAO-style reports normally use metres; US reports commonly show statute miles, such as 10SM, 3SM or 3/4SM.
5. Present weather: No significant present-weather group appears in this example. -RA means light rain, +TSRA heavy thunderstorm rain, FG fog, BR mist and SN snow.
6. Cloud: SCT020 is scattered cloud at 2,000 ft and BKN035 is broken cloud at 3,500 ft. Heights are in hundreds of feet above the aerodrome, not above sea level. The ceiling is the lowest BKN, OVC or VV layer, so this report has a 3,500 ft ceiling.
7. Temperature and dew point: 18/12 means a temperature of 18°C and dew point of 12°C. A small spread indicates moist air and may support mist, fog or low cloud if the air cools sufficiently, but it does not guarantee them.
8. Pressure: Q1016 is an altimeter setting of 1016 hPa. A US report may show A2992, meaning 29.92 inHg. Enter the value using the matching unit or your indicated altitude will be wrong.
9. Trend or remarks: NOSIG means no significant change is expected during the applicable short trend period, commonly two hours where trend forecasts are issued. A section beginning RMK contains supplementary information, especially in North American reports; weather engines may not reproduce every remark.

That pass gives you the report's operational core: where and when it applies, runway wind, visibility, ceiling, surface conditions and altimeter setting.

A more difficult METAR decoded

This illustrative report contains several groups that often slow down new sim pilots:

KDEN 121653Z 01018G28KT 2SM -SN BR BKN012 OVC025 M03/M05 A2985

• KDEN: Denver International Airport.
• 121653Z: observed on the 12th at 16:53 UTC.
• 01018G28KT: wind from 010° true at 18 knots, gusting to 28 knots.
• 2SM: visibility of 2 statute miles.
• -SN BR: light snow and mist.
• BKN012 OVC025: broken cloud at 1,200 ft and overcast at 2,500 ft, giving a 1,200 ft ceiling.
• M03/M05: temperature -3°C and dew point -5°C; the M means minus.
• A2985: altimeter setting 29.85 inHg.

For the simulator pilot, this means poor visibility, a low ceiling, gusty wind, snow and a sub-zero surface temperature. Denver's high elevation does not change the cloud-group convention: BKN012 is 1,200 ft above the airport, not 12,000 ft above sea level.

Snow and a sub-zero surface temperature suggest runway contamination and ground de-icing concerns. They do not, by themselves, define the freezing level or prove that icing exists throughout the route.

Which METAR codes cause the most confusion?

The less familiar groups usually describe automation, variable wind, obscured sky or low-visibility runway conditions.

How do I tell whether a METAR means VFR or IFR?

Use the worse of the reported ceiling and visibility rather than judging the flight from one value alone.

Which cloud layer counts as the ceiling?

The ceiling is the lowest layer reported as BKN, OVC or VV. FEW and SCT layers are not ceilings, so 9999 SCT020 can provide usable VFR conditions while 9999 BKN008 gives an 800 ft ceiling.

The following US weather-display categories are useful planning shorthand, but they are not universal legal VFR minima:

If either value falls into a lower category, use that lower category. Ten kilometres of visibility with BKN008 is still poor VFR weather, while 2 SM visibility is IFR-category weather even with no low ceiling reported.

Actual VFR legality depends on country, airspace, aircraft, time of day and pilot qualifications. Terrain also changes the practical risk: 5 km visibility and a modest ceiling can be far more restrictive in mountains than over flat ground.

When the observation points to instrument conditions, continue with our guide to planning and flying an IFR trip in a simulator. If the destination has an appropriate precision approach, MSFS 2024 pilots can also follow our instructions for setting up and flying an ILS approach.

How do I choose a runway from METAR wind?

Use the wind to identify likely runway candidates, but do not assume the METAR alone tells you which runway is active.

Wind is reported from the direction it is coming. With 24012KT, a runway aligned roughly towards 240° would usually provide a headwind. Published procedures, terrain, traffic, runway closures and tailwind limits can lead an airport or ATC to use another runway.

There is also a reference-direction trap: coded METAR wind directions are true, while runway numbers are based on magnetic direction and rounded to the nearest ten degrees. Runway 24 is therefore an initial clue rather than an exact mathematical match for wind from 240° true, especially where magnetic variation is large.

For a quick crosswind estimate, find the smallest angle between the wind and runway directions:

• 0°: essentially no crosswind.
• 30°: crosswind is about half the wind speed.
• 45°: crosswind is about 70% of the wind speed.
• 60°: crosswind is about 87% of the wind speed.
• 90°: the full wind speed is crosswind.

Use the gust value for a conservative worst-case component, not just the steady wind. A directional variation group such as 180V250 means the component may change substantially during final approach. Our guide to turning METAR wind into crosswind landing technique covers control inputs and go-around decisions.

Can a METAR show fog, thunderstorms or icing?

A METAR can identify hazardous conditions at the reporting station, but it cannot describe the whole route or reliably predict how those conditions will develop.

• Fog and low cloud: FG, BR, low visibility and a small temperature/dew-point spread are useful clues. A narrow spread alone is not a fog forecast; cooling, wind and local terrain also matter.
• Thunderstorms: Look for TS, thunderstorm precipitation such as TSRA, and cloud suffixes such as CB or TCU. A point observation may not represent cells elsewhere around the airport.
• Icing: FZRA and FZDZ directly report freezing precipitation. Sub-zero temperatures plus cloud or precipitation demand caution, but the surface temperature does not reveal temperatures aloft or the complete in-flight icing picture.

Why does live weather not match the METAR exactly?

A simulator can represent the same operational conditions without reproducing every METAR group or cloud layer exactly.

• The report is a point observation: it describes one station, while the weather engine must build a three-dimensional area around it.
• Updates are not instantaneous: weather systems may load reports at intervals and smooth transitions instead of abruptly replacing the sky.
• Some engines blend data: airport observations can be combined with broader forecast-model information away from the field.
• Weather is simplified: cloud coverage, visibility, precipitation, gusts and RVR may not map perfectly to the simulator's available parameters.
• The comparison may be wrong: a different station, an old observation or confusion between UTC and local time can make valid simulated weather appear incorrect.

What should I check when live weather looks wrong?

Verify the report and simulator state before treating the mismatch as a weather-engine fault.

1. Confirm the station: compare the ICAO identifier with the airport where the aircraft is positioned.
2. Check the UTC time: make sure you are reading the latest applicable METAR rather than an earlier report or a local-time conversion.
3. Verify the weather mode: ensure the simulator is using live weather rather than a manual preset, custom theme or saved scenario.
4. Match the pressure units: do not enter Q1016 as though it were 10.16 inHg or A2992 as 2,992 hPa.
5. Allow the weather to load: after spawning or changing weather mode, the engine may need time to populate conditions.
6. Compare operational features: check wind, pressure, visibility category, ceiling and precipitation before judging exact cloud shapes or positions.

Common METAR reading mistakes in flight simulators

Most incorrect weather decisions come from a short list of decoding errors.

• Treating SCT as a ceiling. Only the lowest BKN, OVC or VV layer sets the ceiling.
• Reading cloud height as altitude above sea level. BKN020 means 2,000 ft above the aerodrome.
• Forgetting that wind direction means “from”. Wind from 240° blows towards 060°.
• Ignoring true versus magnetic direction. METAR wind and runway designators do not use the same north reference.
• Missing the M prefix. M05 is -5°C, not +5°C.
• Confusing Q and A pressure groups. They serve the same operational purpose but use hPa and inHg respectively.
• Assuming 9999 means unlimited visibility. It means the reported visibility is at least 10 km.
• Planning from steady wind alone. Gusts and directional variation may create the limiting crosswind or tailwind.
• Ignoring the observation time. A stale report is especially misleading near fronts, showers and thunderstorms.

Our practical scan is: station and time; wind and likely runway; visibility and ceiling; present weather and temperature; then pressure. Repeating that order on every flight catches most METAR errors before departure.