A new Federal Reserve Bank of San Francisco study signals a fresh climate risk for US mortgage rates in 2027
A powerful El Niño weather event could add as much as 1% to US consumer prices over the course of 2027, according to research from the Federal Reserve Bank of San Francisco. The outlook compounds an already difficult rate environment for American mortgage brokers.
Published in November, the Economic Letter from FRBSF economists Molly Arden, Toby Graf, and senior economist Brigitte Roth Tran estimates the current El Niño — classified by the National Oceanic and Atmospheric Administration (NOAA) as “very strong” — may have already lifted personal consumption expenditures (PCE) prices by roughly 0.3% between April and July.
That initial boost is expected to reverse by year-end. If a La Niña episode follows in 2027, as commonly occurs after strong El Niño cycles, the researchers project a net 1 percentage point increase in headline PCE prices throughout that year.
Upward pressure would be concentrated in core services and food categories, both of which are central to the Federal Reserve’s dual mandate of maximum employment and price stability.
3Q GDP came in ahead of forecasts as business spending on data centres and AI infrastructure accelerated. Meanwhile, Mike Fratantoni of MBA notes that inflation remains well above the Federal Reserve's target, keeping future rate hikes firmly in focus. https://t.co/eTbilrWORE
— Mortgage Professional America Magazine (@MPAMagazineUS) October 29, 2026
What this means for the Fed and rates
Any fresh inflationary impulse in 2027 would arrive as mortgage brokers are already navigating some of the highest borrowing costs in years.
The 30-year fixed rate is expected to average 7.5% through all of 2027, according to Fannie Mae’s forecast, a significant upward adjustment from a prior projection of 6.7%.
The Mortgage Bankers Association has taken a similarly cautious view, with its 2027 originations outlook projecting volume will fall 5% to $1.99 trillion as rates are expected to remain above 7% throughout the year.
Mike Fratantoni, chief economist at the Mortgage Bankers Association (MBA) in Washington, DC, previously told Mortgage Professional America that the forces driving elevated rates run deeper than any single policy decision.
“Inflation is too high, leading central banks to raise short-term rates, while budget deficits and debt are unsustainably high, leading bond investors to push up longer-term rates,” he said.
The FRBSF researchers are careful to frame their projections as a risk, not a certainty. The analysis draws on just 22 historical El Niño episodes since the 1950s, only four of which were as strong as the current one.
Whether a La Niña materializes in 2027 — the key variable driving the projected price increase — remains genuinely uncertain.
What brokers face if the outlook worsens
The study lands on a market already under significant strain. Agents surveyed across the US are warning of 2027 home price drops if mortgage rates stay elevated above 7%, with 67% citing affordability as buyers’ biggest obstacle, according to Real REMAX Group’s September 2026 agent survey.
Samantha Shelton, mortgage broker and president at Align Lending in the US, previously told Mortgage Professional America: “When affordability improves, competition increases. That’s why I often tell clients it’s better to be early and refinance later than wait and enter the market with the Black Friday crowd. A buyer who purchases before the rush may get a better price and still benefit when refinance opportunities open.”
If El Niño adds fresh price pressure in 2027, the Fed’s path to rate cuts and brokers’ path to relief could lengthen considerably further.
Stay updated with the freshest mortgage news. Get exclusive interviews, breaking news, and industry events in your inbox, and always be the first to know by subscribing to our FREE daily newsletter.
