My family always has fans on so not necessarily warm clothes but long sleeves my baby almost never wore short sleeves even born in July because I'd have to figure out a blanket
My first daughter was born in May and it was raining the day we had her and the day we brought her home. I would definitely say have some warm clothes on hand for the first month or so until the weather starts to get warmer.
Newborns should be able seeing one more layer than us, our body heat counts as one layer so if they’re in a carrier or napping on you that’s a ln extra layer. Babies until about 10mo should only wear natural fibers to sleep. Ideal inside temp for newborns is 68-72°f