Capitalize a season only when it functions as a proper noun. This happens in three main situations:
In nearly all everyday sentences, seasons are common nouns, not proper nouns. Therefore, they are lowercase. capitalize seasons or not
Days and months have a fixed, singular identity. "Thursday" is a specific name given to a specific day. "Winter," however, spans months and is variable. You can have a "mild winter" or a "harsh winter," but you cannot have a "harsh Thursday" in the same semantic sense. Capitalize a season only when it functions as a proper noun
In this context, the season becomes a proper noun. seasons are common nouns