Originally Posted by
atomic sagebrush
You can get EWCM for days and days before you ovulate.
After the OPK turns pos, you will ovulate anywhere from 8-48 hours after that, average is 36 hours after.
The reason to test at that particular time of day is because the body does follow a rhythm where the LH peaks in the early morning and then it starts to come out in your urine at around lunchtime. So there won't really be a scenario where you miss the surge like that, for the vast majority of people in the vast majority of months.