John Wayne Airport

I am taking a united flight from SNA TO SFO and then to Singapore. How early do I need to be at the airport? Considering the first leg is a domestic, would an hour be sufficient? Or should I treat this as an international hour flight and be 3 hrs early?

Appreciate all inputs!

Update: Got here 1.5hrs earlier before my flight departure. I just finished security. It took me 15mins from bag drop off to get to my gate, on Christmas Eve. SNA FTW!