freezing level

From Wiktionary

Noun[change]

Singular
freezing level

Plural
freezing levels

The red line shows freezing level. Above the line, the air is colder than 0°C. Below the line, the air is warmer than 0°C.
  1. The freezing level is the height where the air is 0 degrees Celsius (0 °C) or 32 degrees Fahrenheit (32 °F). Higher than the freezing level, the air is colder. Lower than the freezing level, the air is warmer.
    Now the weather is colder and the freezing level is lower than it was in the summer.