From the department of Bizarre, Quasi-Animistic Explanations of Everday Meteorological Phenomena, we are proud to present a comprehensive Theory of Rainstorms. Consider:
1) Rainstorms are finite phenomena. That is, they have a beginning and an end.
2) When you look outside and find that it is raining, you usually take an umbrella. You do this because umbrellas keep the rain from falling onto your head.
3) Sometimes, you read the weather forecast and learn that the weather sultans have predicted a rainstorm. Then you take an umbrella with you when you go outside, but sometimes it doesn't actually rain and you carry an umbrella around for nothing.
4) Last week, I read that thundershowers were expected later that evening, and I didn't have an umbrella handy, so I bought one and have been carrying it around in my bag ever since. On three separate occasions, I have left the house to practice for a few hours, carrying my umbrella; each time, it started raining shortly after I started practicing and stopped just before I finished. Today, the rain on the roof was so loud that it almost equalled the sound of the full organ (a 3-manual of about twenty-five stops).
CONCLUSION: Organists can prevent rain by walking around with umbrellas.
So here's a fundraising scheme for your local RCCO/AGO centre: negotiate with owners of golf courses, amusement parks, wedding chapels and other businesses which depend on sunny weather. For a reasonable fee, these businesses can hire an organist to stand outside, holding an umbrella, guaranteeing clear skies for their patrons. Once this relationship becomes an established part of doing business, organists can lobby for additional concessions such as TV coverage of organ recitals, a civic holiday to celebrate the birth of Percy Dearmer, the worldwide abolition of awful electronic church organs, and mandatory worldwide Messiaenological education.
Cynics and scofflaws would argue that this proposal would wreak havoc upon the world's climate and make agriculture impossible, but we've already thought of this; the organists will return home on selected evenings, giving everyone enough advance warning to find a good book and get a good fire going.
(The pathetic fallacy. It's not just a literary trope. It's a way of life.)