off-season; out of season
Refers to produce, seafood, or other seasonal items that are not at their peak season. Can also describe timing that is not ideal for a particular activity.
Off-season vegetables can sometimes lack flavor.
This fish is out of season, so it's not very tasty.
Formed from 旬, “the proper or peak season,” and 外れ, “being outside or missing,” hence “out of season.”