Why has the price of gas jumped 18 cents a gallon?

Why are gasoline prices going up so much? I suppose I should be happy I am paying only $2.69 a gallon for mid-grade, instead of the $4.10 I paid in 2008. But it seems like the economy is not booming and oil supply exceeds demand, which would suggest oil prices -- and hence gasoline prices -- should be dropping. But they're not. And the reason is the same as last year -- speculators.

How much are gasoline prices up? CNN reports they popped 18 cents in the last two weeks. Self-serve regular was $2.655 as of October 23 -- up 17.82 cents since the last Lundberg Survey on October 9. Naturally, there are wide variations in price around the country -- CNN notes that the price is $2.67 in the Midwest; $2.62 on the East Coast; $2.52 for the Gulf Coast; $2.51 in the Rockies. Anchorage, Alaska, at $3.25 per gallon, has the highest price and Tucson, Arizona, the lowest at $2.24.