Seems pretty obvious, but SRTC and other government offices will be closed Monday for the Christmas holiday. SRTC re-opens at 8 a.m. on Tuesday, Dec. 26 but some offices, like Spokane Valley City Hall, remain closed that day so call before heading out to take care of any government business.
As with all holidays, parking at meters is free on Christmas Day so if you come downtown to enjoy the park or something, take advantage of it.