What? No! Winter is when people gather around the fireplace or pub table, drink, chat, and generally don't move for the whole evening.
Speak for yourself.
Since they're confined to staying indoors, the crowds are packed more tightly than in summer.
Not my experience, but I don't recall the last fireplace or pub I've been near. But "confined" shows precisely where the disagreement lies. This shows that you are a summer person and thus are speaking from entirely different assumptions; i.e. that you are outside in the summer and inside in the winter. I speak from the assumption that being outside when it is cold is arguably as fun, if not more so, than in the summer; not the least reason being that there are so fewer people. And if you are inside in the summer, well there are fewer people there now huh? Amazing how easily I solve the introverts problem.
In summer you get barbeques, outdoor sports, beer gardens, etc etc. The crowds are packed much less densely, and it's easier to wander off and get some quiet now and then.
Where do you live? Is it someplace with a low-population density? Because where I live, a less-dense crowd doesn't actually mean that there necessarily
exists a place where you can get away from people. They are everywhere, infesting every spot. Parks are loaded down, and the streets are intolerably hot so you often end up forced inside anyways. Best you can do for quiet is by river, and even
that has regularly high foot traffic (usually joggers and cyclists), even in the locations where it is cut off from the surrounding neighborhoods by a highway.
Ah but the Winter? Different story there. Of course, I've walked through the park after dark in the middle of a snowstorm and
still encountered foot traffic, so absolute solitude is clearly not a luxury the citizens of NYC can afford. But wintertime is, in general, a much closer approximation than the teeming, sweating, moist masses of the summertime.