From 2014 so no idea if it's still accurate:
http://i.slimg.com/sc/aw/photo/t/ts/...date_chart.pdf
Terminal C, West Checkpoint:
Sunday–Friday 5:00 AM–8:00 PM,
Saturday 5:00 AM–6:00 PM;
Terminal D, Main Checkpoint:
Sunday–Friday 5:00 AM–8:00 PM,
Saturday 5:00 AM–6:00 PM