The northern climes are the ones seeing the most heating. I think you can see it most clearly for the month of May. Set the month to May and then click backward

The northern climes are the ones seeing the most heating. I think you can see it most clearly for the month of May. Set the month to May and then click backwards by year through the century, and keep focused on the northern climbs. You can see them colder as you go backward in time.