Question

According to the US Constitution, who decides when the Electoral College casts its vote for president?

Answer 1

The people who decide when the electoral college casts its vote for president is congress because they have been bestowed the power to do that by the US Constitution.

Answer 2

Sorry, my first answer was deleted. I can re-word it in a way where it won't be though.

The Congress (Legislative branch) decides when it is time for the electoral college to vote

(U.S. Constitution, Article 2)

hope this helps.