Well, yesterday I had a headwind all the way out, but technically it was an unfavourable crosswind (SW wind, I was going S). But going back it was a "favourable" crosswind. It just didn't feel very favourable most of the time. The sight of me by the side of the road trying to put on my thin waterproof in a swirling wind, must have amused passing motorists. "Look, a man wrestling with a bright yellow flag".
Oddly, as I rode up the Beacon, the way the wind was swirling, and the way the road twisted, I did have a significant tailwind at one point. Not that it did me much good as I ground my way slowly upwards.