Date to Send SAT Score Reports by?

It says on the application portal that I should have my official SAT score reports sent, but there is no specified date that I could find even upon googling it. Can anyone clarify this?

The score report must reach the UC campuses before the end of December so December 31.

From the UC website: **
If you’re applying for admission to the fall term, be sure to take your admissions tests no later than December of your senior year/last year prior to high school graduation — preferably earlier — to ensure that your application receives prompt and full consideration. It is unlikely that scores from tests taken after our December deadline will arrive in our office in time for our review process