As mentioned above, pilot charts are a good start. There is a
software (I believe it its named Virtual (or Visual?)
Passage Planner, or alike) that repeats the data and lets you browse, plan and calculate the routes according to your boat´s performance / time of the year, etc..
If you browse some online sources like Windfinder, Windguru, Wundergound, etc. and some local mete offices sites´ they may too give you insight into statistical conditions at specific data points.
b.