The one described by the image below was something I did not know about until after my husband and I chose the date and time we wanted for the ceremony. Funnily, it turned out that we unknowingly followed a Chinese tradition because our wedding ceremony began on the upswing at around 6:45pm and I estimate we said our vows roughly around 7:30pm.
When it comes to Chinese wedding traditions, timing is everything. In order to ensure they start their marriage off with good fortune, couples consult with a monk, fortune teller, calendar, or almanac (and these days, the Internet) to find the luckiest wedding day. The selection has to do with a variety of factors, including the bride's and groom's birthdates. And instead of saying their vows at the top of the hour, many Chinese couples start the ceremony at half past the hour, so as to begin their lives together when the clock is on an upswing.
Just a thought.