IPA: /ˌɪn.təˈræn.ju.əl/
KK: /ɪntərˈænjuəl/
Happening between different years or from one year to the next.
The interannual variations in climate can significantly affect agricultural production.
Interannual → It is formed from "inter-" (meaning between) and "annual" (from Latin "annus", meaning year). The word describes something that occurs between or across years.
Think of events that happen 'between' ('inter-') 'years' ('annual') — that's what interannual means.