I was waiting for a SC gardener to respond, but since nothing has happened I suspect my response is the correct one. I use the Quarles planting guide (google it). It appears to be specifically designed for central North Carolina but then suggests 2-3 weeks earlier spring and 2-3 weeks later for fall planting in South Carolina.

Unfortunately, it only gives spring planting dates for peas. Presumably, that means that it is not worth the trouble to grow peas in the fall.

Here is a link that might be useful: Planting Guide

no, i've grown peas for the fall in my fair garden before- i just can't tell you exactly when i planted them, b/c it's been a few years. Seems like it was late august, maybe mid? I know others have done the same for the fair, so it's definitely doable. You're balancing starting too early and having the peas go straight into decline b/c it's too hot with starting too late and losing a lot of your crop to frost.