“To get the best throws, you actually want a slight head wind,” said UMKC physics professor Michael Kruger. “It’s completely counterintuitive. The reason is this: lift is determined by how quickly the air rushes by the discus. (With a headwind), the air is rushing past the discus a bit faster than if it were going in the other direction.
“You know that if you put your hand outside a car while it’s moving. You feel a force backward, but if you tilt it, there’s some force upward. That’s lift. The faster that wind is passing your hand, the greater the lift.”
All the things you wanted to know about throwing a discus but was afraid to ask! :)