Are Mormons allowed to get married on a Sunday?

The Temples are closed on Sundays and Mondays, so no one ever gets sealed on those days. I don't know of any constraint against a civil marriage taking place on a Sunday, except the availability of the chapel. Sundays are busy days in an LDS chapel. Saturdays are the preferred day for a wedding, and usually a chapel can be found at no cost, as long as at least one of the couple-to-be-married is a Mormon. The Temple sealing/marriage is also free, but only faithful members can attend.