Diurnal temperature variation

Temperature lag is an important factor in diurnal temperature variation. Diurnal temperature variation is a meteorological term that relates to the variation in temperature that occurs from the highs of the day to the cool of nights. Heat exchange between this shallow layer of warm air and the cooler air above is very inefficient. As solar energy strikes the earth’s surface each morning, a shallow (1–3 cm) layer of air directly above the ground is heated by conduction. Incoming solar radiation exceeds outgoing heat energy for many hours after noon and equilibrium is usually reached from 3-5 p.m. but this may be affected by a variety of different things such as large bodies of water, soil type and cover, wind, cloud cover/water vapor, and moisture on the ground.