If you were to wake up in a field somewhere and you didn't know which direction was which and the sun was low in the sky... would you be able to tell if it was sunrise or sunset? (You don't have any time telling device with you and you had no idea what time it was when you awoke in the field)
yes, after about 20 minutes. or maybe instantly, depending on how many people are in the field, if the field happens to be located in a reasonably populated area