@hlaurent said in How to Sync My GPX Routing with Windy’s Timeline?:

The route planner is only available with the GFS model so it does not really help and it has a notion of average speed which does not work for a sailing boat

If you mean the Route planner in Windy, it is NOT available with GFS but with the ECMWF model.
However you are right when you says that the Route planner is only based on an averaged speed along the route in Windy.
By the way I see in your screenshot that you did not turn ON this speed button. That would give you a rough estimate of the weather on your route if 12 kt is your averaged speed.