Masaya is famous for its festivals, and the grand-daddy of them all is in honor of San Jeronimo, the city's patron saint. This celebration goes on for a whopping three months, starting in mid-September and continuing, in various forms, until early December.
The biggest days of the festival are from September 27 – October 8. September 30 is the actual saint's day, when the bearded icon is taken from the Iglesia de San Jeronimo and carried around town in a flower-strewn, riotous procession. For good measure, the saint does a victory lap on October 7, accompanied by another huge parade. Of course, the party doesn't end there. The festival continues throughout the following months, waxing and waning in intensity. Celebrations are biggest on Sundays. They generally include music, street dancing, expositions, parades, and a seemingly endless amount of fireworks.
The whole spectacle finally wraps up on the first Sunday of December, just in time for the city to mark the Celebration of the Purisima, a massive Nicaragua-wide religious festival, on December 7.
Masaya also has major celebrations to mark the Dia de San Lazaro on the Sunday before Palm Sunday. Masayans commemorate this feast by dressing-up dogs and bringing them into church. While it may not have the pomp and circumstance awarded to San Jeronimo, I like to think that San Lazaro would be pleased with this somewhat unorthodox tribute.