you could argue that that's because we have such mild weather. in other countries typical changes in the weather are a bigger deal, so it's less appropriate for small talk. this would go some way to explaining why trains stop running when it's very rainy/hot/cold/leafy/snowy. we don't expect the weather to be drastic, and it rarely is, so we're not prepared for it when it happens.

I have no idea whether any of that is true (I doubt it), but it was interesting to write out.