Do you want to define the seasons by temperature? Or by lengthening of the day? Because, to me, seasons are tied to weather in general, but temperature specifically. And temperature seems to correlates to length of day, but trails it by about a month. Which makes sense, since it takes time to heat/cool the enormous thermal mass. So, if weather is how you track the changing of the seasons, it’s close enough to correct as-is.
And which temperatures - air, ground, sea? Or qualitative measures such as when lambs are born, crops are harvested, leaves fall, etc?
There's a lot that we associate with seasons. But the quote somewhere above about six seasons with locking before winter and unlocking after does feel like a better fit to me.
Yeah there are "climatological seasons." The Earth heats up over time, as you say, so the longest day of the year is not generally the hottest day. Climatological summer is June/July/August. The Romans and many other northern hemisphere cultures marked summer as starting before the solstice. I'm not sure when we got the idea that Summer was supposed to start on the solstice.
But it's more than just the temperature, or the day length.
There's a big difference between 40-50°F in November, when the trees are brown and barren, and you're looking ahead to winter, and you swear there's a hint of frost in the air...
...and 40-50°F in April, when the leafbuds are coming out, and the geese are flying back north, and is that a crocus coming up over there?
