In a normal 28 days menstrual cycle when would you expect the LH surge to occur?

Explanation

Ovulation falls at about day 14, and the LH surge precedes it by roughly a day, so it lies in the window from day 11 to 14. The luteal phase after ovulation is the fixed part of the cycle at about fourteen days, which is why counting back from the next expected period is the reliable method. Days 15 to 22 fall after ovulation, when progesterone dominates.