i find the british are pretty chatty, even when its freezing. Yes, warm weather -> people being outdoors -> eventually chat more (and don't do much work)
Sure in the UK somebody might say they're freezing at -5, but in Finland I've been as cold as -25, even in the South.
(People in Finland are better dressed for the weather, and houses are all pretty new, so they're generally well-insulated. But there's probably some truth in the idea that talking to strangers becomes less appealing when you're wrapped in scarves, and winter-gear.)