It depends on the type of sailing and where the race will be taking you. The participants in a race such as the Vendée Globe [0] are almost certainly using the

It depends on the type of sailing and where the race will be taking you. The participants in a race such as the Vendée Globe [0] are almost certainly using the likes of synoptic scale models like the GFS and ECMWF to plan their routes. [0] https://en.wikipedia.org/wiki/Vend%C3%A9e_Globe https://en.wikipedia.org/wiki/Vend%C3%A9e_Globe