<P> In meteorology, diurnal temperature variation is the variation between a high temperature and a low temperature that occurs during the same day . </P> <P> Temperature lag is an important factor in diurnal temperature variation: peak daily temperature generally occurs after noon, as air keeps net absorbing heat even after noon, and similarly minimum daily temperature generally occurs substantially after midnight, indeed occurring during early morning in the hour around dawn, since heat is lost all night long . The analogous annual phenomenon is seasonal lag . </P>

City a has very little variation in temperature over the year