Really? That is interesting. 
Okay you can try this out. Some basic steps. Stay focus, look at
the sky, say a prayer requesting to change the weather. (depend on
your religion, if you have no religion, request it in your own
name)
Most important of all be sincere, show respect and have faith in
your prayer. (You can say the prayer in your mind, don't have to
say it out)
Try it a few times. Also give it a time limit, for example asking
the rain to stop before 6pm or in half an hour time, etc. Work
better this way.
Be beware of energy drained, so don't do it too often. 
May not always work, but 6-7 out of 10 times successful rate is
good enough. Also may not work for some people.
