The patron of Grimacco is Saint Valentine, celebrated on 14 February.
The calendar of the municipality, in the province of Udine, includes on 23 June the «Kries Svetega Ivana» at Costne, in the locality of Luze, a summer solstice festival with the Saint John's bonfire, in November at Liessa the «Senjam beneške piesmi», a festival of Slovene song in the Natisone Valleys, and from 15 to 23 December the «Devetica Božinčna», the Christmas Novena, a traditional Slovene rite with prayers in the houses, songs and night processions with the image of the Madonna.
