BOISE, ID – Idaho gas prices rose by nine cents this week, with the average price for regular gasoline now at $3.33 per gallon, according to AAA Idaho. That’s 15 cents higher than one month ago, but 34 cents lower than the average this time last year.

Nationally, gas prices are averaging $3.17 per gallon. That figure is four cents higher than last week and five cents higher than last month, though still 33 cents less than a year ago.

Idaho currently ranks ninth in the nation for the most expensive fuel. States with higher prices include California ($4.81), Hawaii ($4.51), Washington ($4.19), Nevada ($3.87), Oregon ($3.81), Alaska ($3.45), Illinois ($3.45), and Arizona ($3.34).

“Refineries are in the process of switching from winter-blend fuel to the summer-blend variety, which costs more to make,” said Matthew Conde, AAA Idaho public affairs director. “It is also an opportunity for refineries to inspect their systems and conduct seasonal maintenance. As retailers sell off their remaining winter-blend inventory, the higher replacement cost of summer-blend could result in additional expense at the pump.”

Crude oil prices are also contributing to the increase. After remaining under $70 per barrel throughout March, crude is now trading above $71 per barrel—approximately $2 more than last week and last month, though still nearly $12 less than this time last year. According to AAA, continued increases in crude oil prices could push gas prices even higher.

Regional averages as of March 31 are:

• Boise: $3.34

• Coeur d’Alene: $3.21

• Franklin: $3.19

• Idaho Falls: $3.28

• Lewiston: $3.23

• Pocatello: $3.31

• Rexburg: $3.38

• Twin Falls: $3.36

Additional fuel pricing information is available at gasprices.aaa.com.