Tim's big temperature post serendipitously coincided with my own search for temperature data. On a lark, I decided to test for global warming near my house. With northwestern North Carolina monthly average data obtained from the National Climatic Data Center, I regressed temperature on time with monthly dummy variables and find a statistically significant, positive upward trend.
Click on the image at right to see the results. I used Proc Autoreg in SAS. Durbin-Watson = 1.74, R-squared = 0.95, dummy variables indicate that temperatures increase into the summer and then decrease. The sample size is 756 months from January 1945 to January 2008. The average temperature is 52.68 degrees F. According to the model, average temperatures increase 0.0178 degrees F each year.
In summary, average temperature at my house (roughly thereabouts) has increased by about 1 degree F since WWII.
Update (3/11/08): Maybe.
