According to the Chicago Manual of Style, the AP Stylebook, and other prominent style guides, seasons should not be capitalized unless they are part of a proper noun or a specific event. For example:
There are a few instances where seasons may require capitalization: do seasons need capital letters
Are the Names of Seasons Capitalized? Spring, summer, fall (or autumn), and winter are not considered proper nouns, so they are no... Grammarist When to Capitalize Seasons - Merriam-Webster Do the Names of the Seasons Get Capitalized? ... The seasons are common nouns, not proper nouns, so they are not usually capitaliz... Merriam-Webster Show all Scenario Reason Example Sentence Start Standard grammar for the first word of any sentence. " Winter is my favorite time of year." Proper Nouns When the season is part of a specific official name or brand. "She is competing in the According to the Chicago Manual of Style, the
But language changes. Some style guides (and many people’s intuition) feel seasons are important enough to capitalize, especially when referring to a specific one: “I can’t wait for to arrive.” While not technically wrong in very loose writing, major style guides (AP, Chicago, MLA) all say lowercase. Grammarist When to Capitalize Seasons - Merriam-Webster Do
While the rules of capitalization for seasons are relatively straightforward, it's essential to maintain consistency throughout your writing. If you're writing for a publication or website with a specific style guide, make sure to follow their guidelines. If not, choose a style and stick to it.
That’s a great question, and the short answer is: in standard English writing.