Diesel's street margin is at $1.384 a gallon, its widest in a month

Diesel is the number to watch today. It is at $5.652, the top of its 30-day range and up 6.4 percent over the past month. The retail-to-wholesale spread that sets your counter margin is $1.384 a gallon, the widest that gap has been in a month. Anyone selling diesel off the rack is keeping more per gallon now than at almost any point since late July.

The rest of the barrel is pulling the other way. RBOB gasoline is at $2.954, down 11.4 percent over 30 days and sitting at only the 20 percent mark of its range. Crude is up a little, WTI at $82.49, but the 3:2:1 crack spread has tightened by $14.49 to $57.73. Refiners are making less on the combined barrel than they were a month ago, and that squeeze is landing on the gasoline side while diesel holds firm. For a jobber carrying both, the money is in the diesel gallons right now, not the gasoline ones.

Natural gas is worth a quick look if you burn it or price against it. Henry Hub is at $2.919, up 9.7 percent for the month, and storage is at $109.483, the very top of its 30-day range. Full storage with a firming price is an unusual pair, and it usually means the market expects the gas to move.

The thing to watch is that diesel spread. It is wide because retail has not come down as fast as the rack, and rack prices could catch up if crude stays near $82 and the crack keeps tightening. If that happens, the $1.384 margin may narrow, so it could pay to lock in freight and delivered pricing while the gap is this wide.