A crucial day for inflation and the U.S. economy is off to a bad start.

Diesel prices have hit $6 a gallon for the first time in history and Brent crude oil prices are trading at around $105 a barrel-though they have fallen back from earlier highs of close to $110.

Consumer price index data for August, due to be released at 8.30 a.m. Eastern time, will be closely watched by investors and by Federal Reserve officials. But the live energy prices may give the central bank a clearer picture of inflationary pressures.

The odds of a rate hike next week currently stand at 67%, down from 72% on Thursday, according to the CME FedWatch tool. Cooler-than-expected CPI data later could shift the numbers and the timeline but it now seems to be a question of when the Fed will hike rates and how many times rather than whether they will.

The probability of rates staying at current levels at the end of the year stands at just 6.5%, down from 14% a week ago.

The national average price of diesel has climbed to $6 a gallon, according to GasBuddy data. It comes a week after the previous record of $5.85 was set. A year ago the national average price was around $3.70, it added.

"Record diesel prices will impact every cargo, shipment, every delivery Americans are taking, and are likely to reignite inflation up and down the supply chain," GasBuddy's Head of Petroleum Analysis Patrick De Haan said in a statement.

Wholesale inflation rose 0.4% in August, according to Thursday's producer price index data. But more than a third of the August increase came from a 21.4% jump in diesel prices.

"The surge in energy prices since the turn of the month creates new upside risk for inflation that is not captured by the August PPI report," Bill Adams, chief U.S. economist at Fifth Third Commercial Bank, said Thursday.

"September's surge in diesel prices tips the odds of the Fed's decision next week toward a hike," he added.

Brent crude futures, the international oil benchmark, slipped 2.7% to $104.64 early Friday after trading as high as $109.97 earlier in the session. Oil prices are up more than 70% in 2026 and have risen more than 40% since the start of July.

Oil stocks are having a great week, but were pointing lower ahead of the open Friday. ExxonMobil was down less than 1% having jumped 3.6% this week through Thursday's close. Chevron, Occidental Petroleum and Diamondback Energy also fell less than 1% in premarket trading.