indicating or recording lower than zero on some scale, especially on the Fahrenheit scale: a week of sub-zero temperatures.
characterized by or appropriate for sub-zero temperatures: sub-zero climates; sub-zero clothing for the exploration.

Origin of sub-zero Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sub-zero

Historical Examples of sub-zero

  • The sub-zero temperature of Meta's voice left no doubt as to what she wanted to do with her.

    The Ethical Engineer

    Henry Maxwell Dempsey

  • The Wing Commander stiffened and snorted like a Merlin backfiring on a sub-zero morning.

    A Yankee Flier with the R.A.F.

    Rutherford G. Montgomery

  • We have since found that it can and does heat the entire house even at sub-zero temperatures.

    If You're Going to Live in the Country

    Thomas H. Ormsbee and Richmond Huntley

  • During the day the heat would boil eggs, and at night the sub-zero cold cracked great scales off the granite boulders.

    Loot of the Void

    Edwin K. Sloat

  • They were all bundled in heavy garments, for the temperature of Callisto, never high, frequently drops to sub-zero readings.

    The Space Rover

    Edwin K. Sloat