There seems to be a festival somewhere in the Valley of Oaxaca every week of the year. Oaxaca’s wide ethnic diversity explains much of the celebrating. Each of the groups celebrates its own traditions. Sixteen languages, in dozens of dialects, are spoken within the state. Authorities recognize around 500 distinct regional costumes.

All of this ethnic ferment focuses in the city during the July Lunes del Cerro festival. Known in pre-Hispanic times as the Guelaguetza (gay-lah-GAY-tzah, or Offering), tribes reunited for rituals and dancing in honor of Centeotl, the god of corn. The ceremonies, which climaxed with the sacrifice of a virgin who had been fed hallucinogenic mushrooms, were changed to tamer, mixed Christian–native rites by the Catholic Church. Lilies replaced marigolds—the flower of death—and saints sat in for the indigenous gods.

For the weeks around the two Mondays following July 16, the Día de la Virgen de Carmen (Virgin of Carmen day), Oaxaca is awash with native Mexicans in costume from all seven traditional regions of Oaxaca. The festivities, which include a crafts and agricultural fair, climax with dances and ceremonies at the Guelaguetza amphitheater on the Cerro del Fortín hill northwest of the city.

Entrance to the Guelaguetza dances runs about $30; bring a hat and sunglasses. Make hotel reservations months ahead of time. For more Guelaguetza tickets ($40 per person), contact the state tourist information office (Murguia 206, between Cinco de Mayo and Reforma, tel. 951/516-0123, 951/502-1200, 8 a.m.–8 p.m. daily, info [at] aoaxaca [dot] com, www.oaxaca.travel), two blocks north and a block and a half east of the rear of the cathedral.

Note: If the first Monday after July 16 happens to fall on July 18, the anniversary of Benito Juárez’s death, the first Lunes del Cerro shifts to the succeeding Monday, July 25.

On the Sunday before the first Lunes del Cerro, Oaxacans celebrate their history and culture at the Plaza de Danzas adjacent to the Iglesia de la Virgen de la Soledad. Events include a big sound, light, and dance show and depictions in tableaux of the four periods of Oaxaca history.

Besides the usual national holidays, a number of other locally important fiestas liven up the Oaxacan calendar. The first day of spring, March 21, kicks off the Juegos Florales (Flower Games). Festivities go on for 10 days, including the crowning of a festival queen at the Teatro de Alcalá, poetry contests, and performances by renowned artists and the National Symphony.

On the second Monday in October, residents of Santa María del Tule venerate their ancient tree in the Lunes del Tule festival. Locals in costume celebrate with rites, folk dances, and feats of horsemanship beneath the boughs of their beloved great cypress.

As in many southern-Mexico locales, Oaxaca folks celebrate a robust Día de los Muertos (Day of the Dead) November 1 and 2. Families gather at cemeteries, where they decorate the graves of their departed with the favorite foods of the deceased and lights to guide their beloved ancestors to reunite (albeit temporarily) with the family once again.

Oaxacans venerate their patron, the Virgen de la Soledad, December 16–18. Festivities, which center on the Virgin’s basilica (on Independencia six blocks west of the zócalo), include fireworks, dancing, food, and street processions of the faithful bearing the Virgin’s gold-crowned image decked out in her fine silks and satins.

For the Fiesta de los Rábanos (Festival of the Radishes) on December 23, celebrants fill the Oaxaca zócalo, admiring displays of plants, flowers, and figures crafted of giant radishes. Ceremonies and prizes honor the most innovative designs. Food stalls nearby serve traditional delicacies, including buñuelos (honey-soaked fried tortillas), plates of which are traditionally thrown into the air before the evening is over.

Oaxaca people culminate their posada week on Nochebuena (Christmas Eve) with candle-lit processions from their parishes, accompanied by music, fireworks, and floats. They converge on the zócalo in time for a midnight cathedral mass.