Gregorian calendar September 1

There are 29 days from June 2 to the end of June.

There are 3 1 day in July and August respectively.

September has 1 to 10 days.

So from June 1 to September 10, a total of 29+31+31=10/day passed.

Seven days a week, 10 1 divided by 7 equals 143.

In this way 14 weeks and three days passed. So September 10 is Saturday (Wednesday plus three days).