TIL The largest snowflake ever recorded was 15 inches wide
https://www.guinnessworldrecords.com/world-records/73325-largest-snowflakeOpen linkView original on midwest.socialhttps://www.guinnessworldrecords.com/world-records/73325-largest-snowflakeOpen linkView original on midwest.social
Presumably this was not a single snow crystal, but an agglomeration. More details on large snowflakes here.