1. In January the isotherms deviate to north over the ocean and to the south over the continent. This can be seen on the North Atlantic Ocean.
2. The pressure of warm ocean currents, Gulf Stream and north Atlantic drift, make the northern Atlantic Ocean warmer and the isotherms bend towards the north.
3. Over the land the temperature decreases sharply and the isotherms bend towards south in Europe.
4. It is much pronounced in the Siberian plan. The mean January temperature along 60° E longitude is minus 20° both at 80° N and 50° N latitude. The mean monthly temperature for January is over 27° C in equatorial oceans over 24°C in the tropics and 2° C- 0° C in middle latitudes and -18° C to -48° C in Eurasian continental interior.
5. The effect of the ocean in well pronounced in southern hemisphere. Here, the isotherms are more or less parallel to latitudes and the variations in temperature is more gradual than in the northern hemisphere. The isotherm of 20°C, 10°C, and 0°C run parallel to 35°S, 45° and 60°S latitudes respectively.
