Most women ovulate within 12 to 36 hours after an LH (luteinizing hormone) surge. The LH surge triggers the release of a mature egg from the ovary, and ovulation typically happens in this time frame, though it can vary depending on individual hormone levels and cycle length. Some may ovulate closer to 12 hours after the surge, while others may ovulate as late as 36 hours after the surge. The egg then survives for about 12 to 24 hours after release, marking the peak fertility period.