Danza Cultura Mexicana performs during the 12th annual El Día de San Juan, Wednesday June 24, 2009, in Tucson, Ariz. El Dia de San Juan celebrates the beginning of the 'Season of El Chubasco,' or monsoon rains. The celebration of St. John's birthday (the patron saint of water) was once one of the most important events in Tucson and the Southwest. 

James S. Wood / Arizona Daily Star

June 24 is el día de San Juan, St John the Baptist’s Day, in the Catholic calendar. It was St. John who baptized Jesus in the River Jordan, thus marking the beginning of His ministry. This is why so many of the Mexican traditions associated with this day involve water, and especially running water.

In the old days, people would picnic by (and swim in) the irrigation ditches around Tucson.

One belief was that if you had eye troubles, those troubles could be cured by washing them in naturally running water on June 24. It is as though water, having been used for such a sacred purpose, has special powers on this one day.

Splashing water on others is legitimate on this day, and I’ve been in one central Mexican town where there was a running water fight along the rooftops.

That’s not all that used to happen on that day, of course. There would be the usual fiesta fare — masses, eating, music and dancing, and a special game played by young men on horseback called correr el gallo or running the rooster. A rooster would be buried up to his neck in the dirt, and the players would lean over and try to wrench him loose at a full gallop. In some versions, the other players would try to grab it from him, and a free-for-all would result. A fine time was had by all except the rooster. Needless to say that hasn’t happened in Tucson for a long time.

El día de San Juan is also used for weather prediction. If the summer rains start on the 24th of June, that is a sign that they will be long-lasting and copious. That has seldom happened in my experience; it seems a bit early for that to happen up here. If they even start shortly after the 24th, that’s a good sign.

But if it rains — really rains — all over the valley before el día de San Juan, that is a sign that the saint is trying to warn us about something terrible. “What kind of terrible thing?” I asked my friend Richard Morales. “Oh, famine, pestilence, that sort of thing,” he replied.

Fortunately, there is a traditional hedge to this dire prophecy. The rain must come just before the 24th, I am told, and isolated showers won’t do. It has to rain all over.