all year round - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Throughout the entire year, without regard to seasons. For example, Thanks to the indoor courts we can play tennis all year round. [Mid-1700s]