It's a bit of a cliché, but it's true. The longer any given conversation in Britain, the higher the chance that the weather will be mentioned at some point. This is because it's so varied. It is not uncommon to have all four seasons in a single day. John Cleese once told David Letterman, "We have a national holiday. It's called summer." A big factor in this is prevailing winds. We have the Gulf Stream/North Atlantic Drift from the south west, which prevents the country from getting Canada-level cold (same latitude), but also brings storms. There's also cold winds from the north.