It's best to cover hay before the onset of adverse weather conditions, which often means covering it in late summer or early fall. By covering hay during these seasons, you can protect it from rain, snow, and ice that are likely to occur in the winter months.
This early covering helps to preserve the hay’s quality and prevent moisture-related issues such as mold and spoilage. Covering hay before the weather turns can ensure that it remains dry and in optimal condition for use during the winter and early spring when it is needed most.