<P> Afternoon is the time of the day between noon and evening . It is the time when the sun is descending from its zenith in the sky to somewhat before its terminus at the horizon in the west direction . In human life, it occupies roughly the latter half of the standard work and school day . It is also associated with a number of concerns related to health, safety, and economic productivity: generally, the early afternoon, after most people have eaten lunch, corresponds to decreased work performance, decreased alertness, and a higher incidence of motor vehicle accidents . It is usually from 12 PM to 6 PM, but during winter it may be from 12 PM to 4 PM and during summer it may be from 12 PM to 8 PM . </P> <P> Afternoon is the time occurring between noon and evening . The specific range of time this encompasses varies in one direction: noon is currently defined as a constant 12: 00 pm, but when afternoon ends is dependent on when evening begins, for which there is no standard definition . However, before a period of transition from the twelfth to fourteenth centuries, noon instead referred to 3 pm--possible explanations include shifting times for prayers and midday meals, along which one concept of noon was defined--and so afternoon would have referred to a narrower timeframe . </P>

What is the time between afternoon and evening