The patron of Valentano is Saint John the Apostle and Evangelist, celebrated on 27 December in the Collegiate Church of San Giovanni Apostolo ed Evangelista.
The Fiera del cedro, established in 1461 by Pier Luigi Farnese, is dedicated to local products and all kinds of goods, held on the third Sunday of May and the following Monday. On 14 and 15 August, the Festa del Solco dritto della Madonna dell'Assunta is held instead, a harvest thanksgiving rite that is also propitiatory for new sowing, in which the community entrusts the «Signore della festa» with choosing the most skilled ploughmen. The town also holds the Museum of the Prehistory of Tuscia and the Rocca Farnese.
