The most common and most likely answer to this crossword clue is the 10 letter word SPRINGTIDE
I've seen this crossword clue in The Times
S
P
R
I
N
G
T
I
D
E
More clues leading to the result SPRINGTIDE
Buddy explains!
The straight part
We know that "period of the year" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case period of the year = springtide.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 SPRINGTIDE mean?
SPRINGTIDE noun- The tide which occurs when the moon is new or full; the effects of the Sun and moon being reinforced so that this tide is of maximum range.
- (by extension) A high level of any characteristic.