below freezing; below zero
Refers to a temperature below the freezing point of water, normally below 0°C. Often used before a number, as in 氷点下五度, meaning minus five degrees Celsius.
This morning the temperature dropped to five degrees below freezing.
The road froze in the below-freezing cold.
This morning's temperature was five degrees below freezing.
In this region, nights drop below freezing once winter arrives.
The temperature fell to below freezing, so the water pipes froze.