I know that I can figure out today's date by
NSCalendar* cal = [NSCalendar currentCalendar]; NSDateComponents* comp = [cal components:NSCalendarUnitWeekday fromDate:[NSDate date]]; return [comp weekday]; // 1 = Sunday, 2 = Monday, etc.
See @HuguesBR's answer if you just need the weekday without other components (requires iOS 8+).
NSInteger weekday = [[NSCalendar currentCalendar] component:NSCalendarUnitWeekday fromDate:[NSDate date]];
(If you don't get a correct answer, check if you have mistyped
NSCalendarUnitWeekday with other week-related components like
let weekday = Calendar.current.component(.weekday, from: Date()) // 1 = Sunday, 2 = Monday, etc.