More climate data – global annual temperature variations since 1880

This time I decided to look at the range between the maximum and minimum temperatures annually. The data again is from the Goddard Institute for Space Studies (GISS). (Global-mean monthly, annual and seasonal dT_s based on met.station data, 1880-present, updated through most recent month)

What I thought I would see is a range that grew since 1880. But instead what I observed was that the range grew smaller. But what was even more surprising is that both the maximum temperature and the minimum temperature trendlines were both sloping upwards. This meant that not only were the summer months getting warmer, but so were the winter months!

http://spreadsheets.google.com/pub?key=t1-Xl4C6zccrFEDvd5aBMsg&output=html

 
TMax – trendline for maximum temperature, TMin – trendline for minimum temperature, TRange – trendline for range

I havent seen this analysis before, so if you happen by this post, I would be interested in your thoughts.