Verified answer

I would say, as a native French person:

_ '' Un sentiment d'été ''. Almost the literal translation of your English phrase. It's my favorite for go alongside a photo.

C'est l'ete. Il fait beau.

Voulez vous coucher avec moi ce soir

Summertime = Summer = l'été

The adjective related to Summer is "estival" (ms), "estivale" (fs), "estivaux" (mp) and "estivales" (fp)

But a phrase like "feeling summery" isn't really something very French idiomatically speaking. The problem is that this expression is a little vague and how you would translate it depends on what exactly you are trying to convey.

One possible way to convey the idea that Summer is there is "Ça sent l'été" (It smells like Summer).