There is a concern that near surface temperature is warming in response to human induced changes in the atmosphere or surface. To look at the source data in some detail a JAVA applet was written to make an interative display of some of the RAW DATA used in the trend analyses. An analysis of the daily temperature extremes shows some interesting trends.
Some meteorological stations record the minimum and maximum temperatures for the day.
Karl et al. have analysed these to show strong trends over the last 40 years. In many places the minimum has warmed and the maximum has cooled since 1949. This will allow you to look at some of the source data behind the trend estimates, which hopefully will indicate the difficulty in establishing clear measurements of climate change. The following is an interactive display which will show trends in the temperature maxima. The companion page shows the minimum .