Will U.S. inflation be 4% or higher in the November 2026 CPI report?

The decision that mattered most was in the White House, and it has been made for now. The Associated Press reported on October 8 that Trump posted that the U.S. will not resume military strikes on Iran before the midterm elections and called the talks productive. That closes off the clearest route to a 4% print, an oil shock during the November survey period, at least until November 3.

The pledge fits the incentives. Bombing that sent pump prices up in the final weeks before the vote would cut against the White House's own promise that oil will fall. Breaking a public pre-election pledge would carry its own cost, so we treat a reversal before the survey period as a small tail.

Congress and the administration have used most of their fast tools, and a federal gas tax holiday still has not passed, so the direction of energy prices is being set by the seasonal decline, crude markets and the pace of any Hormuz arrangement.

Reference class: the change in the unadjusted CPI index from September to November in each year from 1990 to 2024. We need roughly a 0.13% rise over those two months if September prints near market expectations (our calculation). That happened in a little over half of all years since 1990, but in only about a third since 2001, when fall gasoline declines became larger. The years that cleared the bar were years when gasoline rose or held up in the fall.

This year, so far, gas is following the normal autumn path rather than the shock path. AAA reported the national average fell to $4.36 on October 8, still a record for the season but below late September. With the September average itself well above August, October is now on course to show only a small energy contribution, not the large one we expected in September.

The 1990 Gulf crisis analogue still marks the upside: oil stayed high into the fall and the CPI rose far more than this question requires. Where it breaks today is the same as before, core inflation then was far higher, and now it would also need fighting to resume.

The arithmetic from version 1 is unchanged: the soft November 2025 base means the November 2026 index must rise only modestly from where September is expected to land. Published previews put September headline CPI, due October 14, between the Cleveland Fed nowcast and a consensus near the high 3s, and New York Fed President John Williams said he expects inflation to end 2026 around 3.5%, below this question's bar.

Start from version 1's base rate of 45%, a blend that puts somewhat more weight on the full 1990 to 2024 record than on the post-2001 record (our weighting). Version 1 added 6 points because pump prices were then running well above the September average; that lift is now mostly gone, so we keep 1 point of it. Keep the 6 point deduction for soft core inflation and the seasonal decline. Down 4 points for the falling trajectory, gas down about 12 cents in two weeks, and a weak September jobs report that points to softer demand. Down 3 points because the pre-midterm pledge on Iran removes most of the strike tail that version 1 priced, leaving it near 4%.

45 plus 1 minus 6 minus 4 minus 3 lands at 33%. A September CPI print well above forecasts on October 14 would move this back toward 40%; a reversal of the Iran pledge with strikes on energy targets would push it above 60%.