When Will I Be Stamped In?

First of all, Happy New Year to all.

The issue: I'm flying from Bangkok to Clark, departure time is 8:55 PM, 17 January. Arrival time at Clark is 1:10 AM, 18 January.

My reason for asking is because I'm arriving Clark only 1 hour into the 18th. So, I wonder if my passport arrival stamp will be on the 18th or the 19th?

Does anybody actually KNOW?

Thanks, always