MAY 1st 2017

In 1870, Pope Pius IX declared Joseph patron of the universal Church and instituted another feast, with an octave, to be held in his honour on Wednesday in the second week after Easter. This was abolished by Pope Pius XII, when in 1955 he established the Feast of "St. Joseph the Worker", to be celebrated on 1 May. This date joins with the May Day (International Workers' Day), a union, workers' and socialists' holiday commemorating the Haymarket affair in Chicago, and reflects Joseph's status as what many Catholics and other Christians consider the "patron of workers" and "model of workers." Catholic and other Christian teachings and stories about or relating to Joseph and the Holy Family frequently stress his patience, persistence, courage, and hard work.
The Feast of Saint Joseph the Worker (1 May) is an Optional Memorial, and so is omitted if impeded, unless the day is raised to a higher rank because Saint Joseph is the patron of the church, diocese, place, or institution. (However, the 1 May celebration is 1st class in the Tridentine calendar, so in it Saint Joseph the Worker was celebrated on 2 May in 2008 because 1 May was Ascension Thursday and in 2011 because 1 May was in the Easter octave.)
courtesy:  https://en.wikipedia.org/wiki/Saint_Joseph