Find out where X-Plane gets real-world weather data, how NOAA, METAR and GRIB fit together, and why X-Plane 11 or 12 may not match reports.
X-Plane gets stock real-world weather through Laminar Research’s online weather delivery service. The service packages aviation observations such as METARs with gridded forecast data for winds and temperatures aloft. NOAA has historically supplied important upstream products, especially for X-Plane 11, but the simulator does not simply read one NOAA weather webpage.
Does X-Plane 11 use NOAA weather? Yes—but NOAA is upstream
Yes: weather products distributed by the US National Oceanic and Atmospheric Administration (NOAA) have historically formed an important part of X-Plane 11’s real-weather data chain.
Laminar’s delivery infrastructure is the service the simulator normally contacts for its prepared weather package. The endpoint shown in Log.txt can vary between X-Plane versions and builds, so references to NOAA and references to a Laminar weather server are not necessarily contradictory: one describes an upstream provider or distributor, while the other describes delivery to X-Plane.
NOAA also does not make every observation itself. METARs originate at airport stations and national weather services around the world, then pass through shared aviation data networks. NOAA can distribute those reports alongside US observations and model products.
How does the X-Plane real-weather data chain work?
X-Plane combines point observations with forecast-model data, then turns them into one continuous simulated atmosphere.
- Stations issue observations. METAR and SPECI reports describe measured or observed conditions at particular airports and times.
- Forecast centres produce gridded data. Numerical models provide winds, temperature, pressure and other atmospheric values between stations and at altitude.
- Laminar prepares a weather package. Its online service collects, processes and caches the information required by the stock weather system.
- X-Plane renders the atmosphere. The weather engine blends those inputs into surface conditions, visibility, clouds, precipitation and winds aloft.
This is why real weather requires an internet connection but is not a live video or radar image. The cloud shapes and transitions seen in the simulator are generated by X-Plane from meteorological data.
What do METAR and GRIB data each provide?
METARs anchor local surface conditions, while gridded forecast data fills the gaps between airports and above them.
| Data layer | What it contributes | What it cannot provide alone |
|---|---|---|
| METAR and SPECI | Surface wind, visibility, temperature, dew point, pressure, present weather and reported cloud layers near an airport | Conditions far from the station or a complete vertical atmosphere |
| Gridded forecast data | Regional pressure patterns plus winds and temperatures aloft | Every small local variation or an exact airport observation |
| X-Plane weather engine | Blending, cloud geometry, transitions and the conditions experienced by the aircraft | A literal reproduction of each report or model grid point |
GRIB is a data format, not a weather provider. A GRIB file can contain output from a numerical forecast model; seeing GRIB mentioned in an error or old setup guide does not identify who made or delivered the forecast.
What changed between X-Plane 11 and X-Plane 12?
X-Plane 11 and X-Plane 12 use the same broad combination of observations and model data, but their weather engines, downloaded files and rendering behaviour are not interchangeable.
X-Plane 11 is commonly documented through downloaded METAR and GRIB data, including references to METAR.rwx. X-Plane 12 introduced a substantially revised atmospheric and cloud system, so an old NOAA weather XP11 procedure that edits or replaces those files may not apply to X-Plane 12.
For the correct controls and signs of a successful refresh, use our X-Plane 12 live-weather setup and update checks. If X-Plane 12 specifically reports that a GRIB file cannot be found, follow our steps for diagnosing a failed GRIB download rather than changing unrelated cloud settings.
Why does X-Plane not match the latest METAR exactly?
A valid real-weather scene can differ from the latest METAR because X-Plane is blending reports and forecasts issued at different places and times.
- Report timing: a new METAR or SPECI may have been issued after X-Plane downloaded its weather package.
- Different positions: a METAR describes conditions at its station, not necessarily several miles away or thousands of feet above it.
- Model blending: the engine must reconcile the station report with neighbouring observations and regional forecast data.
- Cloud interpretation: METAR cloud groups report operationally significant coverage and base heights, not each cloud’s exact shape, depth or position.
- Sparse observations: forecast data carries more weight over oceans and in areas with few reporting stations.
- Stale weather: a failed refresh may leave the simulator using an older successful download.
- Add-ons: a weather injector can replace the stock source, while an environment or cloud add-on may change only how the supplied conditions look.
A mistake we see constantly is treating a METAR as a photograph of the sky. Small differences in wind, visibility or cloud placement do not prove that X-Plane has used the wrong source. When checking reports or forecasts, compare the correct valid time and altitude using our guide to interpreting aviation weather charts for a simulator flight.
When should I reassess a weather mismatch?
Reassess the setup when surface wind, QNH and visibility remain substantially different from a recent airport report after X-Plane confirms a fresh download.
- Investigate if conditions remain fixed through repeated updates or every airport loads the same generic weather.
- Check for a download fault if the log records network, certificate, server or weather-file errors.
- Temporarily remove weather injectors if the simulator reports a successful update but continues to show unrelated conditions.
- Do not diagnose a source failure from cloud shape alone; that is often a rendering or interpretation difference.
How can I check whether X-Plane real weather is updating?
Test the stock real-weather system by itself, then compare basic surface values at an airport that has issued a recent report.
- Select Real Weather. Make sure the weather mode is not set to manual or customised conditions.
- Disable weather-related add-ons. Temporarily remove injectors first; if the data is correct but the sky looks wrong, test without cloud and environment modifications as well.
- Allow a fresh download. Re-select real weather or restart X-Plane after correcting a connection problem rather than assuming the existing session has recovered.
- Compare useful values. Check surface wind, QNH, visibility and approximate cloud bases at a reporting airport. Do not expect identical cloud geometry.
- Inspect
Log.txt. This file is in the main X-Plane folder. Look for weather-download, GRIB or general network errors; the exact wording varies by simulator version. - Check network access. Firewalls, security software, DNS failures and VPN configurations can block the weather service even when ordinary browsing works.
- Verify the computer clock. A seriously incorrect system date or time can interfere with secure online connections and make downloaded data appear older than it is.
If the log records a successful weather download and the main surface values broadly agree with the station report, differences aloft or in cloud placement usually come from model blending and X-Plane’s weather engine rather than a different source.
Does changing X-Plane’s time load historical weather?
No: changing the simulator clock does not make the stock real-weather service retrieve archived or future conditions.
The weather remains tied to the live package available from Laminar’s service, even if the simulator is set to another hour. Our explanation of how time changes affect X-Plane 12 real weather covers the resulting daylight and update behaviour. Use manual weather when recreating a past event or hypothetical forecast.