August 2026 CPI Preview: Could Inflation Ease Again?

August energy prices and mortgage rates moved higher, but the CPI base effect may still allow annual inflation to ease.

The August 2026 CPI report could deliver an important contrast: energy and household borrowing costs moved higher during the month, yet a favorable year-over-year comparison may still allow headline inflation to edge lower.

The official U.S. Consumer Price Index for August is scheduled for release by the Bureau of Labor Statistics on Friday, September 11, 2026, at 8:30 a.m. ET. Until then, fuel prices, mortgage rates and Treasury yields provide useful—but incomplete—signals about the inflation and financial-conditions backdrop.

August 2026 CPI Preview: The Starting Point

The July 2026 CPI report showed headline CPI rising just 0.1% month over month on a seasonally adjusted basis. Annual headline inflation eased from 3.5% to 3.4%, while core CPI slowed to 2.5% year over year.

July’s soft monthly reading was helped by a 1.5% decline in the energy index and a 2.9% fall in seasonally adjusted gasoline prices. Preliminary August tracking suggests that some of this energy relief reversed, although not on the scale of the major price shock seen earlier in 2026.

Preliminary August Price and Rate Signals

Indicator	July 2026	August 2026	Monthly change
Regular gasoline	—	—	+2.433%
No. 2 diesel	—	—	+8.506%
30-year jumbo mortgage average	6.63%	6.69%	+0.06 percentage points / +6 bp / +0.919%
30-year conforming mortgage average	6.58%	6.68%	+0.10 percentage points / +10 bp / +1.523%
Jumbo mortgage spread versus 30-year Treasury	1.406 percentage points	1.455 percentage points	+0.049 percentage points / +4.9 bp
Conforming mortgage spread versus 30-year Treasury	1.436 percentage points	1.469 percentage points	+0.033 percentage points / +3.3 bp

Source: ATN preliminary calculations using August fuel-price observations, mortgage-rate indexes and U.S. Treasury yields. Figures may differ from the final CPI because the BLS uses its own samples, weights, seasonal adjustments and calendar-month methodology. Mortgage rates and spreads are rounded.

Energy Returned as a Moderate Inflation Pressure

Regular gasoline increased by an estimated 2.433% from July, while No. 2 diesel rose a much sharper 8.506%. Gasoline has the more immediate effect on household budgets and the motor-fuel component of CPI. Diesel also matters because it can raise freight, distribution, agricultural and business operating costs before those costs appear elsewhere in consumer prices.

The U.S. Energy Information Administration’s weekly fuel data confirm that pump prices remained elevated through August. However, these figures should be treated as directional indicators rather than a substitute for the CPI release. The BLS explains that weekly external fuel observations refer to particular dates, while the CPI motor-fuel index reflects average prices across the calendar month.

The implication is inflationary, but moderate: August energy prices probably added pressure relative to July, without by themselves proving that broad inflation accelerated.

Mortgage Rates Rose—and Spreads Widened

Average 30-year mortgage rates also moved higher. The jumbo average increased from 6.63% to 6.69%, a rise of 6 basis points. The standard conforming average increased from 6.58% to 6.68%, a rise of 10 basis points. Daily mortgage-index data are available through Optimal Blue’s jumbo series and conforming series on FRED.

The mortgage-rate spread over the 30-year Treasury yield widened modestly in both categories. That suggests borrowers did not receive the full benefit of underlying government-bond pricing and that housing finance remained restrictive.

This 30-year Treasury comparison is an ATN long-duration benchmark. Mortgage and mortgage-backed-securities markets also commonly compare home-loan rates with MBS yields and the 10-year Treasury.

Important CPI distinction

Mortgage interest rates are not a direct component of CPI. The BLS measures owner-occupied housing through owners’ equivalent rent rather than mortgage payments. Mortgage interest, property taxes and home-purchase costs are treated as costs associated with a capital asset and are outside the CPI consumption basket.

Mortgage rates still matter economically. They affect housing affordability, refinancing, construction, household cash flow, transaction volumes and the wider transmission of monetary policy. They are therefore a financial-conditions signal—not a direct forecast of the shelter index.

The August 2025 Base Effect Is the Key

The most important part of the August calculation may be the comparison base. The unadjusted all-items CPI index increased from 323.048 in July 2025 to 323.976 in August 2025, an exact monthly increase of approximately 0.287%.

If the unadjusted August 2026 index rises at the same 0.287% pace, annual inflation would remain almost exactly where it was in July. Using the current published BLS index levels, even an August increase of approximately 0.30% would still leave annual CPI near 3.4% after rounding.

Illustrative August 2026 unadjusted monthly CPI	Implied August annual CPI	Likely published direction
+0.10%	Approximately 3.17%	Rounds to 3.2%
+0.20%	Approximately 3.27%	Rounds to 3.3%
+0.287%	Approximately 3.36%	Rounds to 3.4%
+0.30%	Approximately 3.38%	Rounds to 3.4%

On the current index levels, an unadjusted monthly increase below roughly 0.273% would be sufficient for the annual rate to round down from 3.4% to 3.3%.

This calculation must not be confused with the official seasonally adjusted monthly CPI figure. In August 2025, the widely reported seasonally adjusted increase was 0.4%, while the unadjusted index rose 0.3% when rounded—or 0.287% using the published index levels. The unadjusted series is the correct comparison for calculating the unadjusted year-over-year inflation rate.

Could a Softer CPI Cool the Fed’s Rate-Hike Debate?

Yes—but it would cool the debate rather than settle it.

At its July meeting, the Federal Open Market Committee held the federal-funds target range at 3.50%–3.75% by a 9–3 vote. Three members preferred an immediate 25-basis-point increase. At Jackson Hole, Fed Chair Kevin Warsh also emphasized that inflation remained above the central bank’s 2% target, including on the Fed’s preferred PCE measures.

A decline in annual headline CPI—particularly if accompanied by another restrained core reading—would weaken the immediate argument for raising rates. It would suggest that recent energy pressure has not yet broadened into a renewed general inflation wave.

However, headline inflation near 3.3% or 3.4% would still be above target. The Fed would also examine core services, shelter, wages, inflation expectations and the PCE price index before changing course. One softer report would reduce pressure for a hike; it would not automatically create the conditions for a rate cut.

What the August CPI Could Mean for Markets

Softer outcome

If monthly CPI is restrained and annual inflation falls, Treasury yields could ease and rate-hike expectations could cool. That would be constructive for rate-sensitive equities, small-cap and mid-cap companies, real estate and other sectors exposed to financing costs. It could also reduce some pressure on mortgage affordability and future credit quality.

Near the base-effect threshold

An unadjusted increase around 0.27%–0.30%, leaving annual CPI at approximately 3.4%, would preserve the policy argument on both sides. Markets could remain volatile as investors shift attention to core CPI, employment and the September Fed decision.

Hotter outcome

A meaningfully stronger headline and core reading would reinforce the three FOMC members already favoring higher rates. Long-duration Treasury yields and mortgage rates could remain elevated, while equity valuations—especially in smaller companies and capital-intensive growth sectors—would face renewed pressure.

ATN Conclusion: Inflation Pressure, but Not Yet an Inflation Reacceleration

August produced two visible pressure points. Fuel prices increased, led by diesel, while mortgage rates and mortgage-to-Treasury spreads also moved higher. Consumers therefore experienced no meaningful relief in transportation or new housing finance.

Yet the CPI arithmetic remains more favorable than the surface-level price moves suggest. Because the August 2025 unadjusted CPI base rose by approximately 0.287%, an August 2026 monthly increase below that pace would mechanically lower annual inflation. A reading below roughly 0.273% could be enough to move the published annual rate from 3.4% to 3.3%.

The preliminary balance is therefore cautious but not alarmist: energy is inflationary, financial conditions remain restrictive, but the August CPI could still show a slight further decline in year-over-year inflation. If core inflation also remains contained, the report could cool the hotter voices at the Fed calling for another rate increase.

For related analysis, see ATN’s examination of the Fed rate pause-or-hike decision and the latest look at real retail spending and gasoline pressure.