What is the name of a temporary increase in air temperature in winter or early spring?

Sometimes it happens that in the middle of winter or at the very beginning of spring, the air temperature rises significantly for several days, the air humidity rises, the snow begins to melt, and in general it seems that real spring has come. Such periods are called thaw periods. The onset of the thaw is mainly due to the movement of air masses and a decrease in atmospheric pressure. Thaws are characteristic only for the winter period of temperate and high (northern) latitudes of our planet. Depending on the area, there can be from 8 to 10 such periods during the winter.