We haven't seen gas prices this high in the US since 2008, with Russia's invasion of Ukraine being a primary driver. AAA reports that the average cost of a gallon of gas was $4.17 as of Tuesday morning, per CNN Business. That's a 10-cents-per-gallon increase just from Monday, according to the Oil Price Information Service. So how high can we expect this to go? Citing a forecast by GasBuddy, USA Today reports that the national average for a gallon of gas will peak in May at $4.25. But the average is expected to stay at over $4 until November, and the unpredictability of the war in Ukraine remains in the mix. "I think we'll hit $4.50 a gallon before it turns around," Tom Kloza, OPIS' global head of energy analysis, tells CNN. "Even $5 a gallon nationwide is possible. I wouldn't have predicted that before the fighting started." More on the issue: