when is the NEW iPad Air 3 coming out?

My granddaughter will be needing an iPad this school year and I want to give her the newest iPad Air. The New iPad Air 3 should be coming out, but I don't know when. I will give her my iPad2 to hold her over until the New iPad Air 3 comes out, then she can transfer all her notes, etc to the new iPad. Anybody know any rumors when it this event might happen? Thanks.