The NWS said iguanas are cold blooded, and slow down or become immobile when temperatures drop into the single-digits.
That causes them to drop from the trees, but the service warned they are not dead, just immobilised.
In response to the Tweet, residents have been sharing their own photos of paralysed iguanas spotted on the ground.
Eric Blake posted a picture of one iguana looking decidedly incapacitaed.
"Verification of the @NWSMiami iguana warning! That boy ain't going nowhere...young one couldn't take it (might be dead)."
"Three in North Palm Beach," said Wayne Bartnick, with photograph evidence.
The NWS said the iguanas will reawaken when the sun warms them up.
However, not everyone is sad to see the fall of the iguana.
According to the state's Fish and Wildlife Conservation Commission, the reptiles are an invasive species, native to Central and South America.
While they don't pose a threat to humans - unless they're falling from a tree - they are known for digging burrows and eating through landscaping and foliage, undermining infrastructure.
Last year, the Commission encouraged homeowners to kill green iguanas on their own property whenever possible, due to the destruction they can cause.
While this week has been notably cold in Florida, it hasn't broken any records.
The coldest day was on January 22nd in 1985, when Miami had a low of -1.1C and Fort Lauderdale a low of -1.6C.
