Why does the earth get so cold in winter even it gets hotter?

Conclusion

To summarize, noticeable cold this winter was due to not only one reason but the organic action of complex causes. It was resulted in La Niña with negative Arctic oscillation which made jet stream weaker followed by cold air moves to southward. And anticyclone made in the Ural mountain of Russia also contributed to those abnormal weather conditions.

In January this year, the average temperature of winter was high, but noticeable cold was recorded, indicating that the volatility was great. Through this, we could recognize that the cold snap during global warming, the paradoxical phenomenon, is one aspects of climate change.