Event: Summer and Winter
Sensei asks Sana "shouldn't we go through Fall to get to Winter"
Sana responds: "There is no Fall in Kumon-Mi, just like there is no Spring. I'm surprised you haven't figured that out already."
As in "you've lived here for 30 years, how do you not know the local climate."
For our purposes, Kumon-Mi has Westerosian seasons -- it's summer until it needs to be winter, and then it's winter until it needs to be summer.
The state I used to live in, Florida, has no winter and barely any fall. It does go through all four literally just like anywhere else on Earth, but it is said that Florida only has summer and spring because it almost never gets to fall or winter temperatures due to the climate and geographical layout of the state, being a peninsula in what is more or less a tropical climate.
In the above example, it is meant figuratively to express how the temperature never seems to get out of that summer feel, meaning freaking hot and humid, but the state does go through fall and winter with the occasional dip into cold temperatures.
In contrast, my current state goes through all four pretty clearly. It definitely feels like fall where I am right now.
That's what I meant when I mentioned it not being meant literally. Kumon-Mi might still go through all four seasons, but it may be in a position that doesn't feel like it transitions through all of them. This being set in Japan does make that less likely since Japan isn't like Florida, it does go through all four pretty clearly.
Now, it very well could have been meant in the literal sense and we could very well be seeing a time loop that doesn't allow all four seasons to pass before a reset with some characters being loosely aware of this lack of certain seasons, but I'm not sure of that yet.