sub-zero

adj — 2 senses

adj

Etymology From sub- + zero.

Of a temperature below 0°C; freezing cold

Several days of sub-zero temperatures caused icicles up to 1.5 metres long to form in tunnels across Greater Manchester, Lancashire and Cumbria.2021 February 24, “Network News: NR takes pride in track teams as effects of Storm Darcy repelled...”, in RAIL, number 925, page 13:

US, Of a temperature below 0°F (−18°C)

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.