Wind is a constant nemesis for fly casters, but this is especially true when it’s blowing directly into your casting arm. Every time you lay the line out in front of or behind you, the wind blows it toward you, putting your fly on a collision course with your skull or any projecting features, such as an ear or nose. The best way to deal with this problem is to simply cast with your other hand. No problem, right? Oh, right. You mean you’re not ambidextrous with a fly rod? Yeah, me, neither.
In this excellent clip from his video "Casts that Catch Fish," New Zealand fly-casting instructor Carl McNeil discusses several ways to deal with wind.