αἰθρ-ία · aithr-ia — LSJ
= αἴθρη, first in Sol. 13.22, then in Ion. Prose, Com., X., and Arist.: ἐξ αἰθρίης καὶ νηνεμίης Hdt. 7.188; ἐξ αἰθρίας ἀστράψω Cratin. 53, cf. Hdt. 3.86, X. HG 7.1.31; αἰθρίας οὔσης in clear weather, Arist. Mete. 342a12; αἰθρίης or -ίας abs., Hdt. 7.37, Ar. Nu. 371; τῆς αἰθρίας Arist. Pr. 939b15.
esp. the clear cold air of night, Hdt. 2.68, cf. Hp. Aër. 8. [ῐ in penult. exc. in dact. and anap., Sol. l.c., Ar. l.c.]