Portions of Florida are bracing for unusually frigid temperatures as an extreme cold watch goes into effect over the weekend, the National Weather Service (NWS) says.

American residents across 15 states have been issued with "extreme cold" and "freeze" warnings by the National Weather Service (NWS), as it forecasts that "dangerously cold" wind chills and sub-freezing temperatures are likely to hit affected areas from Tuesday, which could result in hypothermia.