It shows average global temperatures since 1850 based on the global warming stripes by Ed Hawkins, which in turn are based on this data. To be precise, every row represents one year (except for the cuffs). The temperature difference between the colors is 0.1 degrees Celsius. The total temperate difference from the coldest to the warmest year is 1.4 degrees Celsius. All blues and greens are temperatures that are below the global average temperature from 1961-1990. All reds are the years that have been warmer than this average.