Bitter cold temperatures across the United States has increased the demand for heating oil and low-sulfur diesel fuel. The price of diesel fuel increased by 7 cents due to this demand. The average retail price nationwide as of January 10, 2018 is at $2.973 per gallon. This is the highest increase since January, 2015. The highest price per gallon is in the California region at $3.590. The lowest is in the Gulf Coast region at $2.774 per gallon. It is recommended that because of the frigid temps, drivers should keep their fuel tanks full overnight to prevent clogging and freezing.