What you need- Your wand
First off, there has to already be clouds in the sky, I haven't tried it with a clear sky. While outside, raise your wand in the air (if you don't have a wand, use the index finger on your dominant hand). Next, chant:
"The mighty Sun brings the heat,
Right now it's not what I need.
Let the great white clouds come,
And cool down the air some.
The sun may come another day,
But for now, make it stay away.
Clouds deter bad weather from me,
'Tis my will, so mote it be."
Message me if you have any questions or if you tweaked it any, I'd like to know what changes you made so I can try them myself if possible