system
Given the following post, respond as if you're commenting on Reddit:
human
Why does winter (and summer) seem to last longer after the solstice, and is not centered directly around it?

  For instance the average October temperature for Denver, CO is around 51 F, but February temps average at around 33, and March averages 39.  The solstices should be the equal points in solar elevation, but the coldest and warmest points in the seasons always come after them.   February 21 is always colder than October 21 - but they're both equally as far from the solstice.
gpt
It pretty much comes down to the fact that Earth is a giant heat sink. While heading into winter, there is still a lot of latent heat held in the ground/ocean/etc which is keeping the temperature higher. And the opposite as you head into summer, the ground and water is colder, so it takes time to get them heated up again.