In January, the sun shines directly in the Southern Hemisphere. At this time’, the rays of the sun fall vertically on the Tropic of Capricorn, due to which the Southern Hemisphere has summer and Northern Hemisphere has winter season.
The isotherms in this period show the low temperature conditions in the Northern Hemisphere. A center of low temperature develops in the northern part of the Siaberian part of Asia. Here -30 °C isotherm line is found. Temperatures in the Southern part of North America, Southern Europe and south Asian part is depicted by the 10° – 20° isotherms.