Diesel prices continued to climb this week, according to the U.S. Department of Energy.

The average cost for a gallon of diesel reached $4.09, according to Energy Information Administration's weekly report released Monday. That's an increase of 6 cents over last week's average and approximately 27 cents higher than the price per gallon for diesel last year at this time.

The price for gasoline, while not as steep as diesel, is continuing its own upward climb as well. This week, the average price for a gallon of gasoline increase about 3 cents to $3.78.

Diesel prices continue to be the most expensive on the West Coast with California topping the charts with an average price of $4.41 per gallon of diesel.

Due to concerns regarding Tropical Storm Isaac's path across the U.S. Gulf Coast and its potential to affect many of the oil producers in that region, crude oil futures saw an increase on Monday.

Light, sweet crude for October delivery ended the day at $97.14 a barrel, or 1% higher, on the New York Mercantile Exchange.