Orange is out for October because it smacks of Halloween. Trying it with other colors is possible, but combos that are edgy and fun the rest of the year look costume-y in October.
Black is basic, but if you overdo it in October, you could draw out some Morticia comments.
Pink will be associated with Breast Cancer Awareness. Being aware of breast cancer and supporting victims and survivors is not a bad thing; I just don't like that all of a sudden, a color I wear all the time comes to mean one thing. And that thing is breast cancer thanks to all the pinkwashing that goes on.
Rust and chocolate brown and other earth tones will not necessarily say "HALLOWEEN!", but those autumnal colors will blend nicely with the fall décor, and people will comment on that.
You also have to be careful with greens and purples. Depending on the tone, they could go weird and speak Halloween, so I will be sticking with forest and olive and blackberry and saving lime, jade, fuchsia, and royal purple for November.
October is a good time to wear all the red that you can't wear once Christmas hits the store. So go do it.