Despite record setting cold weather in the U.S. last week, which can send fuel and oil prices soaring, diesel and crude prices are down.

Newly released figures from the U.S. Energy Department on Monday show the average cost of diesel has fallen 2.4 cents to $3.886 per gallon. This follows three straight weekly increases, but is only 0.8 cent lower than the same time a year ago.

Prices fell in all parts of the country, with the biggest recorded in the West Coast region minus California, losing 4.3 cents, for an average of $3.891. The smallest drop was in the Central Atlantic part of the East Coast region, down 0.1 cent, for an average of $4.045 per gallon.

Diesel ranges between a low of $3.78 in the Gulf Coast region, down 2.2 cents over the past week, to a high of $4.107 in the New England part of the East Coast region, down 0.8 cent during the same time.

Gasoline also moved lower of the past week, though not as much as diesel, falling 0.5 cent, for an average of $3.327 per gallon, 2.4 cents higher than the same time a year ago.

Prices fell in all parts of the country, except in the Midwest and Rocky Mountain states, where it gained 3.1 cents and 2.8 cents, respectively, though average prices in the two regions were separated by a little more than 10 cents.

Gasoline ranges from a low of $3.108 in the Gulf Coast region, down 1.5 cent from last week, to a high of $3.53 in the New England part of the East Coast region, 2.6 cents less during the same time.

This happened as crude over the past week is down $1.80, setting at $91.80 on Monday at the close of trading in New York, after falling 92 cents on the day.

Before Monday is was up the past few days and before it was announced over the weekend Iran and six world powers, including the U.S., had reached an agreement for easing sanctions against the Middle East country.

This raises the prospect that an additional one million barrels of oil per day could soon be on the worldwide market, which would likely push crude and fuel prices lower.