La Primera Agua de Mayo

I was rooting around, trying to remember that ditty about “30 days have…” because I needed to know when the month was changing, when I remembered my old Cuban granny.
One day many years ago, I was doing something or other in the backyard of our home in Staten Island, when Abuela came running out with a glass of clear liquid, thrusting it at me. “Ruthy, Ruthy, tienes que tomarte esto!” she insisted. “You have to drink this.” I eyed the liquid of indeterminate origin with suspicion. “Que es, Abuela?’ or “What is it?” I asked. “Es la primer agua de mayo,” she informed me, the first rainfall in May. Now we lived across the aptly named Kill van Kull from all the petro refineries in Jersey, and it was not unusual to wake up and find the lawn furniture corroded in the night, which made me a bit hesitant. “Toma la primera agua de mayo para belleza,” or “Drink the first rainfall in May for beauty,” she reiterated. I looked at the glass; I looked at her beaming face, sharing herself, her past with me; and PBC’s or no PBC’s, I gulped it down. Heck, a little beauty wouldn’t hurt either.
So watch out for that first rainfall. I’m a little unclear as to whether it works for guys, but unless you live in Staten Island, it can’t hurt.
Longer version cross-posted at Ninety Miles