Are Season Capitalized Guide
While casual writing allows for some flexibility, if you want to be grammatically correct in professional or academic settings, stick to lowercase.
The short answer is:
Sometimes in business documents or specific formal headers, seasons may be capitalized for stylistic consistency, though this is less about grammar and more about house style. Spring Issue, 2023 Summer Newsletter Comparison with Months and Days are season capitalized
In most everyday writing, seasons are common nouns, not proper nouns. While casual writing allows for some flexibility, if

