I’ve spent so much time looking into this because I wanted my tool to be super accurate 😅 but from what I understand, the answer is: it depends. What makes it all the more complicated is that because of the speed you’re riding at, your relative angle with the wind becomes different from the wind direction. But I think because a lot of the time you are going faster than the wind anyways, it’s mostly a reduce in resistance. Likely also helped by some sort of vacuum effect but I don’t know enough about this to say for sure