One of the consequences of the continuing drought in California has been the unprecedented string of extremely high temperatures that have occurred in the last few years. Normally a portion of the sun’s energy that hits the earth goes to evaporating water from the surface, either from soils or water bodies or indirectly through evapotranspiration from plants.
But with the recent dry conditions, all of that energy is going into raising the temperature. The result of that is a string of three years with temperatures above anything previously seen since official records began in 1895. This comes on top of rising temperatures which show up as a long-term trend in the record (see the graph below). You can read a Bloomberg story from this past week about it here.
You can create a similar graph for your own area using the NCDC Climate at a Glance tool (minus the fancy black and red coloring which was provided by Bloomberg) at http://www.ncdc.noaa.gov/cag.