Seasonal changes in air temperature for fifty years, from 1950_1999. Temperature is colour_coded, from blue coldest to red hottest. The seasonal fluctuation due to the Earth磗 tilt on its axis is evident. High ground such as the Andes has a temperature largely unaffected by seasons due to its altitude. The effect of other systems is also seen _ despite being further south than the British Isles, Newfoundland at the eastern tip of North America is a lot colder, as western Europe is warmed by the Gulf Stream. The original data are from the Global Historical Climatology Network, which is part of NOAA磗 National Climatic Data Centre. The data was interpolated by the Centre for Climatic Research at the University of Delaware.