Rocky Mountain (PADD 4) diesel price

Colorado, Idaho, Montana, Utah and Wyoming make up PADD 4, Rocky Mountain, the smallest of the five districts by population and by diesel volume sold. A handful of refineries serve this large, sparsely populated area with little pipeline connection to neighboring districts, so the market runs closer to self-contained than connected. Thin competition and long hauls to scattered towns push its price up, while refineries running on regional crude pull it down, so its gap to the national average is small and runs both ways, nothing like the West Coast's standing premium.

Because so few refineries supply the whole district, an outage at any one of them matters more here than in a deeper market. Oil and gas drilling activity, a major regional diesel user, adds its own demand swings on top of ordinary trucking.

PADD 4 is the only district that is genuinely small on both sides of the ledger. It has the least refining capacity and the least demand of the five, and the refineries it does have are clustered in a handful of places: the Salt Lake City area, Billings in Montana, and the Cheyenne and Denver corridor in Wyoming and Colorado. They run largely on regional crude, including waxy Uinta Basin barrels and Bakken production, which ties the district's input cost to local production rather than to a waterborne benchmark. What are PADDs explains how a district this small ended up reported alongside four much larger ones.

Isolation cuts both ways here. With little pipeline connection to neighboring districts, PADD 4 cannot easily import its way out of a local outage, so a single refinery going down moves the price more than the same event would anywhere else. It also means a global price shock reaches the Rockies later and softer than it reaches the coasts, because there is less arbitrage running through the district in either direction.

Demand has an industrial shape the trucking base does not explain. Oil and gas drilling is a major diesel consumer across Wyoming, Colorado, Utah and the Bakken side of Montana, and rig activity swings with the crude price, so a strong crude market raises this district's fuel demand at the same moment it raises the cost of making the fuel. Long hauls between scattered towns, high elevation and hard winters add the rest: cold-weather blending runs later into the spring here than in most of the country.

How Rocky Mountain diesel compares with the US average

The gap is Rocky Mountain diesel minus the US average from the same EIA Monday survey, in cents per gallon, so a move elsewhere in the country shifts it even in a week the local price holds still.

For the week of Oct 5, 2026, Rocky Mountain diesel ran 6.8 cents a gallon over the US average ($6.267/gal against $6.199/gal), the fourth lowest of the 10 regional breakouts that week. That is 19.1 cents above its 52-week median of -12.3 cents.

Over the past 52 weeks the gap has run from -46.2 cents (week of Mar 9, 2026) to +6.8 cents (week of Oct 5, 2026). Since EIA's June 2022 survey redesign, Rocky Mountain diesel has priced above the US average in 85 of 226 weekly surveys, and the gap has averaged -6.3 cents a gallon in December through February and +0.2 cents in June through August, so on average Rocky Mountain diesel has sat 6.5 cents lower against the US average in winter than in summer.

The chart above starts in July 2021. Weekly Rocky Mountain prices go back to the week of Mar 21, 1994 on the diesel price history chart, which also tables every region's annual average and record high and low.