Fix an FSX Weather.dll error by resetting weather files, isolating add-ons, and repairing the correct boxed or Steam Edition installation.
A Weather.dll error in Microsoft Flight Simulator X (FSX) or FSX: Steam Edition usually comes from corrupt generated weather data, a damaged saved flight, or a weather injector—not the DLL itself. Test a stock clear-weather flight, rebuild weather and configuration files, disable weather add-ons, then verify or repair FSX if the crash remains.
What does a Weather.dll crash mean?
A Weather.dll entry in Windows Event Viewer means FSX failed while its weather subsystem was active; it does not prove that Weather.dll is damaged. The actual trigger may be injected weather, a malformed saved-flight weather file, corrupt station data, or another module passing bad data to the weather system.
| When FSX crashes | Most likely cause | First action |
|---|---|---|
| Only with one saved flight | Its paired .WX or .FLT file | Create a fresh flight instead of loading that save |
| Only with live weather running | Weather injector, its cache, or its FSX module | Run FSX without the weather utility |
| With every flight | Generated weather data, fsx.cfg, or core files | Rebuild the profile files, then repair FSX |
| When opening the Weather screen or selecting a theme | Modified or damaged weather-theme files | Verify or repair the installation |
| With a different faulting module each time | A wider stability problem | Use broader crash diagnosis rather than replacing Weather.dll |
How do I reset FSX weather files safely?
Reset the generated weather files before touching the installed DLL. Close FSX and every companion utility, then use this order:
- Back up the active FSX profile. The usual folder is
%APPDATA%\Microsoft\FSX. A computer with boxed FSX and Steam Edition installed side by side may use a separate FSX-SE profile; the correct folder is the one whosefsx.cfgtimestamp changes when that edition runs. - Test a clean flight. Start FSX without a weather program, select a stock aircraft and airport, and apply a stock fair-weather theme. Do not load the previous saved flight. If this works, the installed Weather.dll is probably sound.
- Rebuild the station database. In the active profile folder, rename
wxstationlist.bintowxstationlist.bin.old. FSX will generate a replacement when it starts. If the file is absent, simply continue. - Discard the suspect saved weather. FSX saved flights normally have matching
.FLTand.WXfiles in the user's Flight Simulator X files folder. Keep them as backups, but create and save a completely new flight under a different name. Do not restore the old flight as the default until testing is complete. - Rebuild fsx.cfg. Rename
fsx.cfgtofsx.cfg.old, then launch FSX so it creates a clean configuration. This resets display, control and other preferences. Reapply settings manually rather than copying the entire old file back, which can restore the fault. - Isolate weather add-ons. Keep externally launched weather utilities closed. If an add-on starts with FSX, temporarily rename
dll.xmlandexe.xmlin the active profile by adding.offto their names. If the crash stops, restore the files and disable their add-on entries one at a time to identify the offender.
An injector is a higher-priority suspect than a package that only replaces cloud or sky textures. However, any add-on that altered stock weather themes or files should remain disabled until a stock flight runs reliably.
Should I download a replacement Weather.dll?
No. A loose Weather.dll from another FSX edition or patch level can create a version mismatch and make the simulator less stable. Do not register it with regsvr32 or copy one from another computer.
For FSX: Steam Edition, use Steam's file-integrity verification command. For boxed FSX, use the repair option from the original installation media and then restore the same official service-pack or Acceleration level that the installation used before. Steam verification and boxed repair may replace modified stock files, so back up deliberate modifications first.
If the repair process itself fails, our FSX installation-error guidance covers permissions, security-software interference and the differences between boxed and Steam installations.
Can FSX's built-in real-world weather test Weather.dll?
No. The original FSX real-world weather download service was discontinued, so a failed download does not establish that Weather.dll is broken. Use a stock offline weather theme for diagnosis, then reintroduce an external weather engine only after the clean flight is stable.
What if Weather.dll still crashes after repair?
If a clean profile, stock flight and repaired installation still crash, check the Windows Application log again. A repeatable Weather.dll fault points towards a remaining weather add-on, modified theme or per-user file; changing faulting modules point towards a broader driver, memory or system-stability issue.
Do not make a full reinstall the first step. An uninstall can leave fsx.cfg, saved flights and add-on launch files behind, causing the same crash after reinstallation. For faults that are no longer specific to weather, follow our wider FSX crash-diagnosis process to isolate configuration, aircraft, scenery and system causes.