The ambient temperature depends on where the airmass has been before as much as anything.
In UK we are kept warmer than our latitude deserves, by the fact that the GulfStream warms our seas. If the air comes from the same direction, i.e. from the SW, we generally have warm, moist conditions. Conversely, if the wind brings air from the north, it becomes colder.
If we get cold air from the east or north east, watch out at this time of year, that's when we tend to get the really cold conditions (heat lost due to long track over very cold land) plus heavier snowfall at lower elevations. Conversely, in the summer, hotter easterly winds (lots of solar heating over a long land track) will result in "Scorchio" conditions in UK.