The kermis is the carnival. Most towns have a carnival once of twice a year.
The kermis was traditionally a time of courtship, where young folks got together. Some areas had a fair, where young women would line up and young men would select the girl of their choice to take to the carnival and to walk her home at the end of the night.
Sometimes they had such a good time that a hasty marriage was scheduled soon afterwards 😉 If your ancestors had a baby within seven months of their marriage, it is worth checking the local newspapers to see if there was a carnival in town a few months earlier.