Data Visualization
The National Oceanic and Atmospheric Administration (NOAA) maintains a database of chronological climate data available on the web. Every year since 1895, stations all across the continental US have reported monthly values for precipitation and temperature; averages, maximums and minimums.
The plot below considers maximum monthly temperatures from 1895 to 2012. For each month and year, a set of 118 values were fit to a least squares regression line. The slope of this line was recorded and indicated by a green slash yellow dot below. The black line indicates zero slope and therefore zero change in value across the 118 years on record.
It is clear from the plot that many more stations are increasing in temperature rather than decreasing.
To add relevance, the plot is animated to associate various dots with specific geographic stations. The dots are arranged alphebatically in columns by state name, so Alabama comprises the first few columns and Wyoming the last few.