This is how horrifically they have left us all living in very different random pot luck, and all perceiving our own local bubbles as the general reality and not thinking that it can be very different in other regions. Before the web, we were unable to know that either.
You can say now, in 2024, that In your local experience shorts uniforms are still the general norm. In South Wales, I was able to grow up a half-century ago without knowing they existed, and to start infants class in private school in 1973, yes private school 1973 in Cardiff, with longs allowed and seasonally taken for granted and no notion of otherwise. Followed later by the hated unbearably bad luck that I was naively, and disastrously in outcome, sent to another school that was hot on gifted fantasies, and as part of its dismal businesslike atmosphere, did not allow shorts at all above the first primary year, which was age 8.
I have seen several posts online by folks newly discovering to their shock that shorts uniforms still exist. Throughout my childhood the media never discussed school trousers, never showed me that shorts uniforms existed, nor my mother who believed any question of shorts in winter had ended when the old mid-century boys' costume went out. Equally, it never showed the folks living those uniforms that there were places like South Wales where they were not a visible thing.
Nor did the royals show us, as we were in the gap between Princes Edward and William. Only once was I tantalised, a tad puzzled, and racked with envy, to see 2 schoolboys of my age singing carols on Nationwide in shorts, but I supposed it just had to be the TV studio warmth that enabled that unseasonal style. Around when I was 10, exactly when South Wales catarrh had made my most serious attempt to stay in shorts at home right through an autumn appear to fail.
This is why I ask all the folks with happy experiences. Would your kid still have found their year round shorts choices, and made them in confidence of not being harmful, if you were living before the web and you did not have the idea already existing among school peers ? If you were completely on your own with the idea, would you or your kid have known they were not going to catch cold/chills ? Or did you find and make those choices only because you had that information, either from peers or from the web ?