is it too hot for baby to wear long sleeve onsie and pants?

My daughter is 6 months old and its 80 degrees out but i the next hour it will drop to about 75 or so. I want to put her in a long sleeve white onsie with black pants. Is it too hot? She will be in shade of course when we take her out. I bought this outfit a long time ago and shes never worn it. I dont want her to outgrow it, its too cute!