I took about 10 years of gas price data from around Southern California (AAA So Cal) and input the data in Excel. I had quarterly surveyed data points.
Using an add-on tool called Megastat, I had Excel come up with a model so I could use it to predict future gas prices. Once I had my initial model, I back correlated the prices to check for accuracy and it was nearly dead-on.
With that in mind, using the model I determined that gas will hit (on average) $4/gallon by Spring 2009 (May specifically) in So Cal.
