Yup - we all get 'em.
Warren's right, they're not caused by the wind, although in a high wind they can get a bit more common as you tire more quickly. Try a longer pause at the front and especially back of your casting arc. This gives the line time to straighten out before you start the rod in the other direction, which will reduce (as Warren said, not end) the number of tailing loops and consequent wind knots.
This is also the secret to longer casts, because your line loads the rod as it straightens completely, bending it away from you, and causing it to spring the line back in the opposite direction when you stop your stroke at the opposite end of your arc.