A new industry survey shows gas prices rising nearly 12 cents in the past 2 weeks.
The national average now sits at $3.41 a gallon.
The spike comes as oil prices rise in response to heightened concerns over recent violent unrest in Ukraine, Venezuela and South Sudan.
Gasbuddy.com has been forecasting more expensive gas because of the start of annual refinery maintenance for the shift to summer fuels.
Other factors include higher oil prices and lower output from European refineries.