The alert, from the National Weather Service, came as the southern state was hit by temperatures dropping to an uncommonly cold -1C.
That’s low enough to freeze the blood of iguanas, which, in turn, can lead to the animals losing their grip on the tree branches where they live and result in them plummeting to earth.
"This isn't something we usually forecast,” the service in Miami tweeted, “but don't be surprised if you see iguanas falling from the trees tonight as lows drop into the 30s and 40s. Brrrr.”
The warning was arguably much-needed: given that adult males an reach 5ft in length and weigh in at 20 pounds, they could be potentially dangerous to anyone standing underneath when they fall.
And experts also told residents it was best not to approach the stiff and chilled creatures if spotted: they may unexpectedly thaw and attack.
“Like any wild animal, it will try to defend itself,” Kristen Sommers, from the Florida Fish and Wildlife Conservation Commission, told the Washington Post last year.