Diesel futures are at 4.244, near the top of their 30-day range

Diesel is the number to price against today. ULSD futures are 4.244, up 33.6 percent over the past 30 days, and that puts the contract at the 82 percent mark of its 30-day range of 3.093 to 4.496. Every other benchmark on the board is closer to the middle of its own range. Brent is 100.63 at the 62 percent mark, WTI is 92.2 at the 54 percent mark, and RBOB gasoline is 3.315 at the 55 percent mark. Diesel is leading the barrel, and it is doing it from the top of the range rather than the middle.

The retail side has not kept up. The diesel retail-wholesale spread is 1.015, down 0.724 over the past 30 days. That is about 72 cents a gallon of street margin gone in a month, and it comes off every gallon a site pumps. Wholesale went up faster than the street did, which is the usual shape when the rack runs. Refiners are on the better side of it. The 3:2:1 crack is 60.03, wider by 5.21 over the past month, so the barrel is paying more to crack than it was, and diesel's 33.6 percent run against gasoline's 15.0 percent is where most of that came from.

Natural gas is the quiet one. Henry Hub is 2.915, down 9.5 percent on the month, while storage is 99.776 and is at the 98 percent mark of its range. Full tanks and a soft price go together.

Watch whether retail catches up to the rack. The diesel spread has room to rebuild if ULSD holds near 4.244 and the street keeps posting, though a pullback in the futures could close that gap from the other direction instead.