December Temperature Trends

By using the Pennsylvania temperature data from 1899 to 2002 on the Pennsylvania State Climatologist website, I constructed a graph to show the linear trend of December temperatures throughout the century for climate division 1 (northwest PA). From year to year, average temperatures fluctuated with an irregular pattern, ranging from 15 degrees Fahrenheit to 36 degrees Fahrenheit. Some of the highest and the lowest average temperatures recorded in this region occurred in the past 30 years. Using a five-year running mean, the overall trend of these temperatures indicate that there has been a slight temperature rise of 1 to 2 degrees in the state of Pennsylvania in the past 103 years. This temperature rise has been hypothesized to be related to the increase of greenhouse gases in the atmosphere.