Afternoon begins at 12:01 p.m. and ends at 6 p.m. Many consider sunset to be the ending time for afternoon, but that leads to a large difference in afternoon ending times, from 5 p.m. in mid-winter to 9:30 p.m. in mid-summer.
One way to figure the start and end times for morning, afternoon, evening and night is to use the meteorological time, which must agree worldwide for forecasting. Meteorologists consider morning to be from 6 a.m. to 12 p.m. Afternoon lasts from 12 p.m. to 6 p.m. Evening runs from 6 p.m. to midnight. Overnight lasts from midnight to 6 a.m.