Answer:
Well actually, the shortest day (winter solstice) is NOT actually the coldest day of the year!
Step-by-step explanation:
The shortest day of the year is called the WINTER SOLSTICE and happens on December 21st or 22nd (it varies per year)
It can't really be called the COLDEST because of the SEASONAL LAG: the gap between the Solar changes/positions in season and the Climatic changes (ie...the Autumnal Equinox is the start of autumn but it could still feel like summer)
The SEASONAL LAG means that the Earth's coldest temperatures of the Winter would happen AFTER it has changed into winter...this means the Winter Solstice can't really be the coldest! :D
Let me know if you need any help!