Much depends on time of day. Out west here the strong west winds are typically in the afternoons. Often there's a light east wind in the morning. Timing is everything.
My XC trips have all been eastbound, and I've been very happy for some of those afternoon tail winds. I tend to plan my days to catch them. I could just as well plan my days to avoid them. One memorable eastbound trip across Montana included five days of very strong tailwinds all day. The westbounders I met then were miserable.
I also have noticed prevailing winds to be SW.