below freezing

The average temperature in a local area must be zero degrees Celsius - or less - for seven days in a row, or be forecast to be below freezing for seven consecutive days.

Temperatures will be much lower than the mid-November average by day - and may reach below freezing by night.

Where clear skies last through the night temperatures are likely to drop below freezing.

Temperatures in the desert can reach up to 120 degrees Fahrenheit in the summer months and dip below freezing during the winter.

As winds fall lighter overnight it is even possible that Friday morning could start with an air frost - where temperatures drop below freezing.