seasonal

seasonal /ˈsiːzn̩əl/ adjective
seasonal
/ˈsiːzn̩əl/
adjective
Britannica Dictionary definition of SEASONAL
1 
: happening or needed during a particular time of the year
2 
: normal for a certain time of year

— seasonality

/ˌsiːzəˈnæləti/ noun, technical [noncount]

— seasonally

adverb