Astronomically… Winter starts on 21st December

Astronomically, winter starts on December 21, 2020, at 14:03 UAE time and continues until March 20, 2021, then enters spring season. Ibrahim Al Jarwan, member of the Arab Union for Astronomy and Space Sciences, explained that at the beginning of the winter season the length of the night is longer in the northern hemisphere while the day gets shorter.

Then the day increases gradually until it reaches the equinox at the beginning of spring.