The most common and most likely answer to this crossword clue is the 8 letter word GRITTERS
G
R
I
T
T
E
R
S
Buddy explains!
The straight part
We know that "They are out on cold nights" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they are out on cold nights = gritters.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GRITTERS mean?
GRITTERS noun- A vehicle that applies grit to icy roads to improve traction