The price of oil is inching back closer to the $100 a barrel mark while diesel fuel prices, rising for the fourth straight week, hit their highest level since the latter half of October.

Crude oil gained $1.31 per barrel Monday in New York trading, closing at $97.03 as the Euro strengthened against the dollar, making it a more attractive buy for foreign investors. The price has gained nearly a dollar over the past week, despite small swings back and fourth. This is the first time it has closed above the $97 mark in more than a week.

Diesel increased for the fourth straight week according to a new U.S. Energy Department report, adding 8.2 cents from last week, for a U.S. average of $4.104 per gallon. In mid January, when it recorded its last weekly decline, the average cost was $3.894 per gallon, its lowest level so far this year.

The latest price is 16.1 cents per gallon higher than the same time a year ago.

Diesel picked up in all parts of the country with gains of 10 cents per gallon or more recorded in the Midwest and Rocky Mountain regions. It ranges from an average of $3.964 in the Rocky Mountain region to $4.266 in New England, though the West Coast is close behind it at $4.265 per gallon.

Other average regional prices include the East Coast, $4.152; Central Atlantic, $4.216; Lower Atlantic, $4.083; Midwest, $4.08 and Gulf Coast, $3.997. California’s average prices came in at $4.331 per gallon.

Gasoline prices, according to the DOE, are up for the sixth straight week, to their highest level so far this year, averaging $3.611 per gallon and up 7.3 cents over last week. The last time the average price of gasoline declined was the first week of the year, which was its lowest level so far in 2013, at $3.233 per gallon. Prices increased in all regions of the country over the past week, with averages between $3.274 in the Rocky Mountain region to $3.867 along the West Coast.