This morpho-lexical type appears on the AIS map 313 ("L'AUTUNNO", AUTUMN in the Belluno Ponte nelle Alpi (P. 336)). Among the reference dictionaries, the Treccani dictionary is the only one that lists this type. However, this form does not refer to AUTUMN in general, but rather to the expression used by Venetian fishermen to refer to the specific autumn period when fish retreat from the lagoon to the open sea.
Other dictionaries indicate that the type is found not only in the south of the Veneto and in Ponte nelle Alpi, but also in other varieties in the province of Belluno, especially in Agordino. It occurs in Zoldo Valley as well, this time in the meaning of 'autumn' (cf. Rossi 1992, 314, under fardìma; Pallabazzer 1989, 189, under ferdíma). It is interesting to note that this form extends only as far as the territory of the so-called Sellaladinia and does not cross its boundaries (cf. Blad under auton).
This morpho-lexical type belongs to the base type lat. frigĭdus ('cold') (FEW 3, 797 under frigĭdus).