1
general::
Phrase(s): all year round
Fig. throughout all the seasons of the year; during the entire year. • The public swimming pool is enclosed so that it can be used all year round. • In the South they can grow flowers all year round.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Throughout the entire year, without regard to seasons. For example, Thanks to the indoor courts we can play tennis all year round. [Mid-1700s]
American Heritage Idioms