It's because most of the year we're only in a narrow range of between 5 and 25 degrees, for most of the country and maybe 0-30 for most of the extremes (-5 to +35 is less than 1% for most places). It's quite a narrow range, the UK is pretty much one of the safest places in the world as far as harsh weather and temperature variations go, and in the north east of England we're also in pretty much the safest part of it. A lot of European countries deal with much larger extremes than we do, and they're more common.