system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are the seasons not centered around the summer and winter solstice?

If the summer and winter solstice are the longest and shortest days when the earth gets the most and the least amount of sunshine, why do these times mark the BEGINNING of summer and winter, and not the very center, with them being the peak of the summer and peak of winter with temperatures returning back towards the middle on either side of those dates?
gpt
It takes a long time for the oceans to heat up and cool down, and to a lesser extent, rocks.  This means that the actual weather temperatures and weather patterns experienced lag the day length by some time.  In Europe, for example, the Atlantic Ocean reaches its maximum temperature around September, and the ocean temperature is important in setting weather patterns in places with maritime climates, or even a fair distance inland.  This means that although the longest days are in June, the hottest months are July and August.