환절기가 · 환절기를
change of seasons (period)
Example
환절기에는 감기에 걸리기 쉬워요.
It's easy to catch a cold when the seasons change.
Word parts
환 change+절 season+기 period
Literally 'season-changing period'.
Good to know
환절기 감기 조심하세요 'watch out for colds at the change of season' is a common caring remark; the big gap between day and night temperatures gets the blame.
Related words