adjective
or es·ti·val ˈestəvəl, (ˈ)es|tīvəl, Brit usually -ēs-
Etymology: Middle English estival, from Middle French or Latin; Middle French, from Latin aestivalis, from aestivus of summer (from aestas summer + -ivus -ive) + -alis -al; akin to Latin aedes temple — more at edify
: of or belonging to the summer
the sky was a burnished aestival blue — Irish Statesman