Poisson d'avril is held on April 1. France, Switzerland, French Community of Belgium. This event in the first decade of the month april is annual.
Näfelser Fahrt in Glarus, Switzerland on April 3 (The Battle of Näfels was fought on 9 April 1388 between Glarus with its allies the Old Swiss Confederation, and the Habsburgs. It was a decisive Glarner victory);
Easter in Western Christianity on April 4 (Første påskedag in Norway);
Malbec World Day on April 17 (Malbec is a purple grape variety used in making red wine. MWD is celebrated to commemorate the day when president Domingo Faustino Sarmiento of Argentina officially made it his mission to transform Argentina's wine industry. On that day, back in 1853, he tasked Michel Aimé Pouget, a French soil expert, to bring over new vines);
Sechseläuten in Zurich on April 19 (the third Monday in April);