Why Custom Weather Matters for Prepar3D

Prepar3D (P3D) is a powerful flight simulation platform used by enthusiasts and professionals alike. While the default weather engine provides basic conditions, custom weather setups unlock a new level of realism and scenario control. By importing real-world METAR data, historical weather, or artist-crafted themes, you can create everything from calm clear skies to severe storms. This guide covers the entire process—from understanding weather file formats to advanced configuration—so you can tailor the atmosphere to any flight.

Prerequisites: What You Need Before Starting

  • A working install of Prepar3D (v4, v5, or v6; steps may differ slightly in menu layouts).
  • Weather data files – these can come from add‑ons like Active Sky, REX Weather Force, or manually created METAR text files.
  • Basic file management skills – you’ll need to navigate folders and copy/rename files.
  • Active internet connection – necessary if you plan to download live data or community‑created weather packages.
  • Optional but recommended: a third‑party weather engine such as Active Sky for real‑time injection, or REX for high‑definition textures and themes.

Most commercial add‑ons store weather files with .wx (REX) or .metar extensions. You can also find thousands of free weather profiles on sites like AVSIM or FlightSim.com. Knowing your file format is the first step toward a successful custom setup.

Step 1: Locate or Create Your Weather Files

Where to Find Ready‑Made Files

Many flight sim communities share weather presets. Look for files with .wx or .metar extensions. The .wx format is proprietary to REX products and contains both weather parameters and cloud textures. The .metar format is plain text that follows standard aviation weather codes. You can download real METAR data for any airport from NOAA Aviation Weather and save it as a .metar file.

Creating a Custom METAR File

Open Notepad (or any text editor) and type a valid METAR string. For example:
KSFO 022356Z AUTO 32010KT 10SM SCT030 BKN250 18/13 A2998 RMK A01
Save the file with a .metar extension. You can use online METAR decoders to learn each element (wind, visibility, sky condition, temperature, pressure). This method gives you full control but requires some knowledge of aviation weather codes.

Organise Your Files

Create a dedicated folder such as C:\Users\[YourName]\Documents\P3D_Weather. Keep your custom files together; this will make importing faster and help you avoid clutter.

Step 2: Enter Prepar3D Weather Settings

  1. Launch Prepar3D and wait for the main menu screen.
  2. Click the Options button (gear icon) at the top of the screen.
  3. Select Weather from the left‑hand navigation panel.
  4. You’ll see the Weather Configuration window. In P3D v5 and v6, this includes options for Weather Mode (Theme, Download, Custom) and Advanced Weather.

If you are using a third‑party add‑on (like Active Sky), you may need to disable its built‑in weather engine first or configure it to inject data into P3D. For the native method described here, ensure Weather Mode is set to Custom or Manual.

Step 3: Import Custom Weather Files

Using the Built‑In Importer

In the Weather menu, click the Import button. A file browser will open. Navigate to the folder you created in Step 1. Select one or multiple files (hold Ctrl for multiple). After importing, the weather them will appear in the list under “User Defined Weather”.

Importing .wx Files

If you are using REX products, the .wx files should be placed in the correct add‑on folder automatically. However, you can manually import them via the same button. Note that REX files also carry texture information; the sim will load the matching cloud and sky textures when you apply the weather.

Importing .metar Files

Plain .metar files are treated as a single station observation. P3D will interpret the data and create a static weather condition based on that METAR. This works well for recreating a specific real‑world moment.

Verify the Import

After importing, the weather name should appear in your custom list. Click on it to see a summary of conditions (temperature, wind, visibility). If the file contains errors, the sim may ignore it or show default values. Check the METAR syntax or ensure the .wx file is from a compatible source.

Step 4: Configure Weather Parameters

Fine‑Tuning Basic Settings

Once a custom weather file is loaded, you can tweak individual parameters in the Advanced Weather section. Adjust the following:

  • Wind: speed and direction, both at surface and aloft (layers up to 30,000 ft).
  • Temperature: values from -50°C to +50°C.
  • Visibility: range from 0 (fog) to 99 statute miles.
  • Precipitation: rain, snow, or mixed intensity.
  • Cloud coverage: types (cirrus, cumulus, stratus) and layers (up to 4).

Using Multiple Layers for Realism

Realistic weather is rarely a single uniform condition. Enable “Layered Weather” to define conditions at different altitudes. For example, a low overcast layer at 3000 ft, with high cirrus at 25,000 ft and calm surface winds. P3D will interpolate between layers, providing a more dynamic feel.

Setting Weather for Multiple Regions

If you fly cross‑country, you can import different weather themes for departure, en‑route, and arrival. To do this, go to the Weather tab and select “Advanced Weather”. Choose “Themes” from the drop‑down. You can assign a different theme to each part of your flight plan. This feature requires some experimentation but yields immersive transitions.

Third‑Party Tools for Enhanced Control

Add‑ons like Active Sky for Prepar3D provide live weather injection with far more granularity than the native importer. Active Sky can download up‑to‑date METARs, SIGMETs, and even volcanic ash data, then smoothly adjust conditions during your flight. However, even with such tools, it’s beneficial to understand the native method so you can create custom profiles offline.

Step 5: Save and Apply Your Custom Weather Profile

  1. After adjusting all parameters, click Save As. Give your profile a descriptive name (e.g., “Stormy_Approach_KSFO”).
  2. By default, profiles are saved in the %PROGRAMDATA%\Lockheed Martin\Prepar3D v5\Weather folder (version‑dependent).
  3. Ensure the saved profile is selected in the weather list. Then go back to the main menu, choose an aircraft, airport, and time, then start your flight.
  4. During flight, you can open the weather menu (Alt → World → Weather) to see if conditions match your settings. If not, verify that the profile is still active and that no add‑on is overriding it.

Creating Multiple Profiles for Different Scenarios

You can save dozens of profiles. For example:

  • Clear and Cold: high pressure, < -10°C, no clouds.
  • Mountain Thunderstorm: strong surface winds, cumulonimbus, rain, low visibility.
  • Foggy Approach: 200 m visibility, overcast at 200 ft, stagnant winds.

Save each under a separate name. This is especially useful for checking specific instrument procedures (ILS approaches in low IFR).

Advanced Tips and Troubleshooting

Performance Considerations

Heavy weather (thick clouds, multiple layers, rain) can hit frame rates. If you notice stutters, reduce the number of cloud layers or lower the cloud draw distance. P3D v6 offers improved performance with volumetric clouds, but the native system still benefits from conservative settings.

Combining Custom Weather with Dynamic Time

Weather does not automatically change with time unless you use an add‑on like Active Sky. If you want a static custom profile to appear at dawn or dusk, adjust the time/day in the main menu before starting the flight. The lighting will change but the weather remains constant.

Common Pitfalls and Fixes

  • “Weather file not recognised”: ensure the extension is .wx or .metar and the file is not corrupted. Try downloading from a reliable source.
  • Weather resets to default: another add‑on might be overriding the native engine. Disable it in the add‑on menu or within its settings.
  • No precipitation despite METAR showing rain: some METAR codes for showers are not perfectly interpreted. Manually set precipitation type and intensity in the advanced options.
  • Clouds not matching .wx textures: REX textures require the corresponding texture pack to be installed. Verify that REX is running and the textures are active.

Where to Find More Resources

Conclusion

Custom weather in Prepar3D is not just a visual upgrade—it fundamentally changes how you experience each flight. By mastering the import process, configuration sliders, and layered systems, you can recreate historical storms, practice low‑visibility approaches, or simply enjoy a perfect visual‑flight day. Start with simple METAR imports, then progress to designing your own themes. With the techniques described here, you will have the tools to make every departure and landing an authentic, immersive challenge.