These names remind me of autumn either in their meanings or in their associations with autumnal colours or themes (e.g. harvest).
Please note that a number of names will have various origins and may hold different meanings in different cultures. I always recommend doing your own research! I also based the "gender" column on traditional usage but of course you're free to name characters of any gender whichever name you please.
Name | 
Explanation | 
Gender | 
| Rufus | Red-haired | Male | 
| Carmine | Deep red | Unisex | 
| Sharad | Autumn season | Male | 
| Amber | Fossilised resin / honey yellow | Female | 
| Oisin | Little deer, fawn | Male | 
| Ceres | Goddess of harvest | Female | 
| Alon | Oak | Male | 
| Sienna | Orange-red colour | Female | 
| Ember | A small, glowing fire | Unisex | 
| Rory | Red king | Male | 
| Taran | Thunder | Unisex | 
| Hazel | A type of tree and nut | Female | 
| Akihiro | Bright, autumn | Male | 
| Orlaith | Golden princess | Female | 
| Russet | Reddish-brown color | Unisex | 
| Jora | Autumn rainfall | Female | 
| Rowan | A type of tree | Unisex |