That’s according to a new study looking at how palm trees are expanding into northern parts of the world that have long been too cold for the iconic tropical trees. As climate change warms the planet, countless plants and animals are migrating into new habitats made more suitable for their survival. The scientists also discovered that the palms’ evolutionary heritage also plays a role in their ability to tolerate different temperatures. In a new paper published in Nature Scientific Reports, researchers from Columbia University’s Lamont-Doherty Earth Observatory, Brandon University, and the University of Saskatchewan sifted through thousands of data points to untangle the relationship between temperature and distribution of palm trees, and offer hints about where the trees could put down roots in a warming world. If that average is above 2 degrees Celsius, or 36 degrees Fahrenheit, the palm may be able to successfully propagate in the wild. According to Tammo Reichgelt, a Lamont-Doherty Earth Observatory researcher who led the study, this means that at an average of 34 degrees Fahrenheit in January, Washington, D.C. is just a little too cold to host palm trees, “but that you can expect range expansion in the coming decades as average winter temperatures warm up.” 
 
 Looks like the National Arboretum might need to make room for some new species. “Palms are therefore sensitive indicators of changing climates, both in the remote geological past and in the present day ,” study co-author and Brandon University researcher David Greenwood said in a release. Greenwood told Earther that the Chinese windmill palm (Trachycarpus fortunei) is especially cold hardy, and is commonly cultivated for this reason. Advertisement 
 
 “A little bit more warming will see their seedlings survive winters.” 
 
 Greenwood said for a palm to colonize a new region, its seedlings must be able to survive their first winter. “But this is of course changing as the climate gets warmer.” 
 
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 Greenwood said parts of the Northeast, Northwest, and neighboring areas of Canada are close to a winter climate that could allow cold-tolerant palms to become established. “In all of these areas, palms in people’s gardens are flowering and setting fruit, which means the temperatures are now warm enough for that step in their reproduction,” he said. “A little bit more warming will see their seedlings survive winters.”
– Utah, Ohio, and Canada might soon be dotted with palm trees—because welcome to climate change. Following a 2007 study that found palm trees in the foothills of the Swiss Alps, an international team of researchers set out to learn how cold is too cold for palm trees. Upon surveying global data, they determined most palm species (there are 2,500) grow successfully in the wild if a region's coldest month is above 41.36 degrees Fahrenheit on average, per Atlas Obscura. A handful of cold-tolerant palms, like the windmill palm, however, can grow in areas with a coldest month temperature above 36 degrees on average. With an average temp of 34 degrees in January, Washington, DC, isn't quite there, researchers say, but they note it could warm enough "in the coming decades" to allow palms to flourish, reports Weather.com. The same goes for the Northeast, Northwest, parts of Canada, and other parts of the world that have long been too cold for palms. "In all of these areas palms in people's gardens are flowering and setting fruit," study co-author David Greenwood says, per Earther. But "just because you can grow a windmill palm or another cold-tolerant palm in your yard in Utah, British Columbia, or Ohio, doesn't mean that species can colonize the nearby woods." For that to happen, seedlings—which are less tolerant of the cold than adult plants—must be able to survive their first winter, and that will take "a little bit more warming," Greenwood says. The study in Scientific Reports also looked at palms in the fossil record, noting their presence suggests a minimum temperature of roughly 36 degrees. (Los Angeles is losing its palm trees.)