In-N-Out, Weirdly, Is a Climate Change Indicator

It’s Fast-Food Week! Enjoy these articles animal-style.

On March 10, In-N-Out Burger opened its 389^th store, in Delano, California. The first customer arrived early, while it was still dark. Parking-lot lights illuminated two newly planted palm trees, leaning at nearly 45 degrees, roped together to form the burger chain’s iconic “X marks the spot.” Shining after the rain, bright-green fronds still ponytailed from transit, the trees looked a bit like svelte, spray-tanned troll dolls.

Sam Vonderheide pulled past the trees and into the drive-thru. He ordered a Double-Double, fries, and a 2x4 (a Double-Double with two extra slices of cheese). One more grand opening down: Vonderheide had now visited every single In-N-Out Burger with his kids. Drive-thrus, a welcome escape from the pandemic lockdown in July 2020, had quickly became a quest. The trio started near their home in central California, then worked their way north into Oregon and east out through Arizona, Nevada, Utah, Colorado, and Texas.

In-N-Out Burger, founded in 1948, is endemic to the Los Angeles County suburbs; it reached Northern California and Las Vegas in the 1990s. Despite more recent expansions, most locations are still in the chain’s natural habitat: hot, dry, sunny sorts of places.

“I don’t see us stretched across the whole U.S.,” said third-generation In-N-Out owner and president Lynsi Snyder in a 2018 interview with Forbes. Yet In-N-Out is creeping eastward: In January, In-N-Out announced that it plans to open stores in Nashville, Tennessee, in 2026.

When the Nashville In-N-Out news broke, Vonderheide quickly called his mom, who recently moved to South Carolina, to tell her the good news: In-N-Out would again be within reasonable road-trip distance. I also saw the news, which I digested while sipping a shake from one of the chain’s palm-tree-print paper cups. It raised a pressing question: Do palm trees even grow in Nashville? And if they don’t, what is In-N-Out doing there?

Aesthetically, In-N-Out Burger is all-in. Iris Apfel has her bug glasses; In-N-Out has its palms. “It’s kind of their thing,” Vonderheide agreed when I spoke with him. Tiny red palms dot the restaurants’ wallpaper. Palms adorn wrappers, awnings, paper hats—and, usually, parking lots. Scan California’s freeways and you’ll see them everywhere: a pair of palms swaying in the breeze, standing sentry over your beloved animal-style fries.

Palm-free In-N-Outs are somewhat rare. “I counted my list,” Vonderheide told me. Out of nearly 400 stores, he estimates, “probably 50 In-N-Outs don’t have the crossed palm trees.” A store in Thornton, Colorado, planted palms when it opened in 2022. Ahead of winter, it wrapped them in heating wires. “That was mighty optimistic,” wrote one Coloradan on Reddit. The internet documented first their decline, then their stumps.

Grants Pass, Oregon, rejected In-N-Out’s palm tree plans in 2017, apparently after watching a similar scene play out at the chain’s Medford, Oregon, store. “They tried them in Medford and they just end up looking really bad as they deteriorate,” wrote the Grants Pass Chamber of Commerce, according to Oregon NBC affiliate KOBI-TV5. Jason Lovell, the nursery owner who was going to deliver the palms, ended up planting them in his own yard instead. He claimed that the problem wasn’t the weather, but the soil. “They planted them in solid sand,” he told the Grants Pass Daily Courier. “You can’t do that here.” In-N-Out Burger declined to comment.

I double-checked Tennessee’s palm tree credentials with palm tree guru Donald Hodel, horticulturalist emeritus for the UC Cooperative Extension in Los Angeles County. “There are a couple of short, stubby palms that might grow there,” Hodel said.

But, he confirmed, Nashville is probably too cold for the classic In-N-Out tree. That, he told me, is the Mexican fan palm, Washingtonia robusta, which only survives down to about 15 degrees Fahrenheit. Their tall, fast-growing trunks, tied together, make the classic In-N-Out X. The palms In-N-Out had planned for Grants Pass were a more cold-hardy variety: Chinese windmill palms. They might survive in Nashville, but would make for a smaller X; in cold climates, they don’t grow more than 10 feet. Nashville’s local palms, the dwarf palmetto and Sabal minor, might, at best, yield a fluffy lowercase m.

“We prefer that our restaurants feature crossed palm trees, and most of them do,” an In-N-Out spokesperson told me in an email. So why, then, after multiple failed attempts, were they at it again, trying to manifest a palm-filled destiny in yet another hostile climate? Maybe In-N-Out knows something about the future.

In the 1963 film It’s A Mad, Mad, Mad, Mad World, a favorite of In-N-Out founder Harry Snyder, palm trees mark buried treasure, and serve as a major plot device. At Harry’s store, crossed palms mark a treasured fast-food experience: fresh buns, patties, and fries made daily.

But for researcher Tammo Reichgelt, palms mark something else entirely: temperature extremes, and the contours of a changing world.

A paleobotanist at the University of Connecticut, Reichgelt uses ancient palms to build climate models because they are great temperature indicators. Unlike trees that go dormant in winter, he explained, “if the sap stops flowing, they die.” Sap can circulate in below-freezing weather if a palms’ roots stay warm; skirts of leaves warming the trunk can also help, he said. If you know a palm’s lethal temperature along with the boundaries of its historical range, you know how cold a place got millions of years ago.

Palms related to Mexican fan palms and Chinese windmill palms, Reichgelt told me, once stretched to Alberta, Canada. “Palm pollen, which is less attributable to a specific group, has been found as far as the North Pole,” he said. Studying modern palms can help make ancient maps more accurate; those ancient maps in turn help tell us how the climate might change next.

As the planet heats back up, palms are again on the move. Chinese windmill palms grow in Ticino, Switzerland, which is known for its balmy weather. Now, though, they are expanding beyond Ticino’s lakeshores to become a quickly spreading invasive species in the forests of the Swiss Alps. “They’re the canaries in the coal mine, basically, for indicating that the vegetation realm is shifting,” Reichgelt said.

I asked how long until palms make it back to Alberta. “I would say we’re a good hundreds-of-years away from that,” he said. “Just hundreds?” I asked. “That becomes more of a policy question than a scientific question,” he said. (In other words, it depends on whether we get our carbon emissions under control.)

But while Alberta might be hundreds of years off, what about In-N-Out’s service area? Many gardeners are familiar with the USDA’s Plant Hardiness Zone system: The lower temperature limit for Mexican fan palms, around 15 degrees Fahrenheit, is right in the middle of Zone 8. For gardeners in 8b, these palms have a good chance. In 8a, microclimates and coddling may help them beat the odds, but they usually get too cold. That is, of course, weird winters aside: Most of Texas is in Zone 8, but the 2021 Big Freeze pushed temperatures 45 degrees below normal, killing 90 percent of Austin’s palms.

Medford, Oregon, sits right on the line between 8a and 8b; the In-N-Out is currently on the slightly-too-cold side for Mexican fan palms. But that line is moving. The USDA has a map of how the Plant Hardiness Zones will change under different emissions scenarios. It doesn’t differentiate between 8a and 8b, but it does show the Medford area moving further from Zone 7 and closer to Zone 9 under all scenarios. If the Medford store just waits a decade or so to try Mexican fan palms, it may be in luck—in the meantime, it could also try Chinese windmill palms, which should thrive in 8a and survive down to Zone 7b. (In-N-Out did not confirm which species it had already tried.)

Nashville is currently in Zone 7a, dicey even for Chinese windmill palms; right now, all of Tennessee is Zone 8a or colder. By midcentury, though, under an emissions-as-usual scenario, Nashville will be a little Zone 8 oasis—cities tend to be hotter than surrounding areas. So will Salt Lake City (where In-N-Out already has stores), along with the Boise, Idaho, metro area (where the company has a store opening in September), and even Grand Rapids, Michigan (well within driving distance of a Nashville burger-distribution hub).

Most of the South will be palm-friendly much sooner—well within the lifespan of a forward-thinking business. Colorado In-N-Outs will likely remain palm-free. But—if global climate goals aren’t met—New York City is on track to move into Zone 9 by midcentury, and would easily support L.A.-style Mexican fan palms. (An uncannily perfect Double-Double was spotted on a Queens sidewalk in 2019; perhaps it was an omen after all.) As the world warms, and we continue to get burgers, fries, and shakes without leaving our gas-guzzling cars, at least something will be flourishing.