The waters around IONAIONA Islands Of North Atlantic. Yes I know there's an island called Iona, but this is so I don't have to use the term 'British Isles' when referring to the whole of Ireland and the UK. are all still well above average for early January. In fact the southern North Sea is +1.7°C above the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO., and has been for some considerable time. It’s no wonder when we do get a cold Arctic northerly or a continental easterly, why temperatures are even more attenuated by the SSTSST Sea Surface Temperatures than they usually are.