Are ranged attacks by spells affected by the wind? In the amended 4E rules for Magic Missile, the spell always hits, so I suppose we can take the answer for that spell to be that no, the cover and wind are irrelevant.
What about other arcane missile attacks? Eldritch Blast, for example, requires a roll to hit versus the target's Reflex defense, implying that the target can leap out of the way of an aimed projectile. The roll, though, is based on Charisma or Constitution, used (possibly?) to channel arcane energy from the warlock's patron. If the blast is only magical energy, perhaps it too is unaffected by the wind.
An likely upcoming combat in what amounts to a wind tunnel has me wondering whether there is a clear answer to this question in the enormous corpus of D&D 4E rules, or even some other rule which seems to apply by analogy. In the absence of a rule finding or excellent argument, I am happy to simply make a ruling based on my whims — I'm just curious as to whether there is a more specific "official" rule.