The most common and most likely answer to this crossword clue is the 8 letter word SEASONAL
I've seen this crossword clue in The Guardian
S
E
A
S
O
N
A
L
More clues leading to the result SEASONAL
- Fashion on sale as at certain periods
- A boy dives into lock, depending on the time of year
- A sale’s on possibly for part of the year only
- Main salon’s modified according to time of year
- Take part in cruise, as on a liner during summer, perhaps?
- Pepper old gangster every so often
- Secure a child inside, specifically for Christmas period, say
- Aquatic mammal bearing one child, but only in the summer?
- It describes winter sale a son organised
- Timely introduction of a native to sea loch
Buddy explains!

The straight part
We know that "depending on the time of year" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case depending on the time of year = seasonal.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 SEASONAL mean?
SEASONAL noun- Anything that is seasonal, such as a financial trend, a product for sale, or an employee.
- Of, related to or reliant on a season or period of the year, especially with regard to weather characteristics.