Weather Tidbits: Winter Seasonal Lag

This Weather Tidbits discusses seasonal lag during the winter. Seasonal lag is the phenomenon where the maximum (minimum) air temperature is delayed after the date of maximum (minimum) solar radiation. This means the hottest and coldest days of the year, occur after the summer and winter solstices. The coldest temperatures of the year for the Northern Hemisphere tend to occur in January. Temperatures across the United States are coldest in December in the West; while the East goes frigid in January. The exception is the Rockies where it takes place in February or March. This is due to snowpack reflecting incoming sunlight, thus keeping temperatures colder.