1. Ripening season: September melon is named because its ripening time is usually in September, while August melon ripens in August. This means that the melons ripen later in September, while the melons ripen earlier in August.

2. Appearance characteristics: There are some differences in appearance between September melon and August melon. September melon is usually oval, with light yellow or green skin and sometimes dark green texture. August melons are generally round or oblate, with smooth skin and yellow or light green.