unusually (compared to a typical year)
Used to describe something that is different from the norm for that time of year, often implying a notable deviation.
See also: 例年
This year there is unusually a lot of snow.
The cherry blossoms bloomed unusually early this year.
Standard kanji spelling.
Alternate spelling using 無く; less common.
From 例年 (typical year) + に (particle) + なく (adverbial form of ない, 'not'). Literally 'not being like a typical year'.