$4 gasoline is right around the corner for Valley drivers.  

Gasoline price tracker GasBuddy.com says the average for a gallon of gas in Sacramento is up 6 cents in the last week and up 30 cents in the last month to an average of $3.72.  

Analysts say the seasonal volatility at the pump is driven by refinery maintenance and a switch to the summer gasoline blend among other factors.