The most common and most likely answer to this crossword clue is the 10 letter word SUMMERTIME
S
U
M
M
E
R
T
I
M
E
Buddy explains!
The straight part
We know that "when it’s warm" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case when it’s warm = summertime.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 SUMMERTIME mean?
SUMMERTIME noun- The period or season of summer.