Ovulation can occur during the day or at night, because ovulation time is not a fixed time and ovulation is not very related to day and night. If you have regular menstruation, ovulation can occur about 14 days before your menstrual period. You can test for ovulation by ultrasound or ovulation test strips, which are recommended every 2-3 hours to determine the approximate time of ovulation. The time of ovulation is related to the level of hormones in the body and the size of the developing follicles, so it is best to check regularly. If you plan to get pregnant, it is best to have intercourse two days before the day of ovulation to increase your chances of getting pregnant. The egg can survive in the vagina for two days after ovulation and the sperm can survive in the woman’s body for 2-3 days, so having intercourse around the time of ovulation has a very good chance of getting pregnant. If you do not intend to get pregnant, it is recommended that you use condoms or birth control pills for contraception.