This week I learned: the NOAA maintains a database of rainfall levels, in mm/hour, for every 8km x 8km area on earth, for every 30 minute period since 1999. And you can download it. It's ~90GB compressed. It's formatted as a fortran data dump, of course.
Job continues to amuse.
 At the equator. Narrower elsewhere. They seemingly didn't bother collecting data above 60N or below 60S; maybe it never rains there. I don't know how weather works.