what is the maximum length of luteal phase
Luteal phase The human luteal phase lasts between ten and sixteen days, the average being fourteen days. Luteal phases of less than twelve days may make it more difficult to achieve pregnancy. While luteal phase length varies significantly from woman to woman, for the same woman the length will be fairly consistent from cycle to cycle.[5]
Daytime Although the daytime length at the Equator remains 12 hours in all seasons, the duration at all other latitudes varies with the seasons. During the winter, daytime lasts shorter than 12 hours; during the summer, it lasts longer than 12 hours. Northern winter and southern summer concur, while northern summer and southern winter concur.