Christmas Eve in Mexico typically starts at midnight on the night of December 24th, when families gather together to exchange gifts and celebrate the holiday. It's a time for family and friends to come together and enjoy each other's company, eat delicious food, and share in the joy of the season. It's a very festive time of year, with many people decorating their homes with Christmas trees, lights, and other decorations. In some regions, it's also traditional to attend midnight mass or participate in other religious rituals.