....
I would think that the reason weathermen use the cardinal points system
rather than actual degrees is that it gives them some leeway in their
estimates of what direction the wind will blow from, ...

Good point. If you are using data from an automatic reporting station
or a digital model then you will get a report in degrees. Of course,
even in the precise area of the station or grid the wind will vary over
time and forecasts all have some level of error as well. WX reports
usually try to predict conditions over time and area which adds more
uncertainty. It all gets pretty fuzzy, pretty quickly.

-- Tom.