Interestingly enough, if you aren’t familiar with the location, there’s no foolproof method to tell whether it’s morning or evening by light alone. There may be cues, like if it’s a city then the properties of light could reflect the denser pollution it has to penetrate in the evening, but that still depends on location and time of year.

I sincerely thought I could tell mornings from evenings by light alone, until I congratulated a friend on a great capture of evening light and he told me the shot was taken in the morning. Did some research after that.