Mapping the climate change

So, let's roll up our sleeves and perform some geospatially informed data analysis.

For our problem, we'll look at how the climate change affects the continental United States over the last century or so. Specifically, we'll look at how the average maximum temperature for July has changed. For North America, this should give us a good snapshot of the hottest temperatures.

One nice thing about working with the weather data is that there's a lot of it, and it's easily available. US National Oceanic and Atmospheric Administration (NOAA) collects it and maintains archives of it.

For this project, we'll use the Global Summary of the Day (http://www.ncdc.noaa.gov/cgi-bin/res40.pl). This includes daily summaries from each active weather station. We'll filter out any weather stations that aren't in the US, and we'll filter out any data that is not in use for the month of July.

Climate is typically defined on thirty-year periods. For example, the climate for a location would...