Franklin Graham commented before praying for the benediction at the inaguration that it was raining, and rain is a sign of God's blessing in the bible. I recall that not being 100% true.
Genesis 7:
4 Seven days from now I will send rain on the earth for forty days and forty nights, and I will wipe from the face of the earth every living creature I have made.
22 Everything on dry land that had the breath of life in its nostrils died. 23 Every living thing on the face of the earth was wiped out; people and animals and the creatures that move along the ground and the birds were wiped from the earth. Only Noah was left, and those with him in the ark.
