photo of students walking the student unionStudent Union building hours are:

7 a.m.-11 p.m. Monday-Friday
8 a.m.-11 p.m. Saturday
10 a.m.-11 p.m. Sunday 

The Student Union building hours are subject to change during break periods and emergency closures. Office hours and services are contingent upon the specific office in the Student Union.

The Student Union has been designed to be the students' community center and "living room" on campus, and provides easy access to nearly all student services under one roof. 
Download Student Union Building Information (PDF) to see all areas/rooms, room numbers, and phone numbers.