I have understood that Windy has not planned to offer historical data:
If the historical data would allow you to know the weather observations, day after day, during 10, 20 or 30 years. Then a statistical treatment and data compilation would be necessary to calculate the average strength of the wind, its direction on large ocean areas. At lot of work ...
The most simple for a long passage is to use the Pilots Charts. These maps are available month by month, and are based on observations from many years. They are free.
Example for November month.
You can download them via this website: