I have a week of ewcm, sometimes as early as cd8.
This, but I've also had ewcm for 4ish days, then nothing for a week or two, then ewcm again for 4ish days and an actual temp shift. This was back when I had long cycles. I hear it is common when you have pcos to gear up for ovulation once or twice (with nothing happening) before actually ovulating. But I don't have it so someone else can feel free to chime in.