Argimusco is a district in the neighborhood of the medieval city of Montalbano Elicona, in northern Sicily. It is a plateau, a suggestive naturalistic area that is near to many interesting archaeological sites, like Rocca San Marco and Sperlinga, whose origins date back respectively to the Paleolithic and Mesolithic Age (Brea in La Sicilia prima dei Greci, Il Saggiatore, Milano, 1958; Cavalier Il riparo della Sperlinga di S. Basilio (Novara di Sicilia), in Bullettino di Paletnologia Italiana, Roma, pp. 7-76, 1971). The Argimusco's plateau has natural rock formations featuring anthropomorphic and zoomorphic forms. It is assumed that the entire area had been used since the prehistoric times as a place of worship and ritual use, and, according to some sicilian scholars, it could be a sort of natural sanctuary (Pantano in Megaliti di Sicilia, Edizioni Fotocolor, Patti, 1994; Todaro in Alla ricerca di Abaceno, Armando Siciliano Editore, Messina, 1992). Unfortunately, official archaeological excavations were never made on the Argimusco's plateau, but, from several surveys, lithic and pottery fragments have emerged ranging from the prehistoric age to the late medieval period. Argimusco appears to be a good site for the observation of the sky and of celestial phenomena (Orlando Archaeoastronomy in Sicily: Megaliths and Rocky Sites, in The Materiality of the Sky, Sophia Centre Press, 2016). In this paper I present the results of a 6 years of study of this area, and I propose a possible calendar based on the eastern horizon profile characteristics with Rocca Novara that acts as an equinox indicator.