system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the shortest day of the year (when sub exposure is at its lowest) not more correlated with the coldest time of the year?

Another way to ask this is why isn’t the winter solstice not the mid point in winter?
gpt
Because there is a lag as things continue to cool down. The coldest part of the morning isn't midnight, its just around dawn, because the ground continued to release its heat through 1am, 2am, 3am, 4am, and even when the sun first appears, its at such an angle that the ground can continue cooling a bit. 

The same principle applies to winter. There's some pent-up heat built up from summer. If you keep getting only winter levels of sun, it can still get cooler.