Leila,
Lahinch attracts windsurfers mainly from Galway and Limerick. Usually in a NW (cross shore , starboard) and when there is swell.
Lauch just past the pitch and putt course over the river (towards Liscannor end of beach).
Other Clare venues as Dan said are Fanore in a Se or S nad closer to you , Quilty in a SW. Quilty is partially sheltered from the swell but gets nices reef breaks working towards high tide.
Mark