What month did Mormon trail start?

Answer 1

The Mormon Trail was used for 21 years, from 1847 to 1868. The first groups began leaving Nauvoo, Illiois in February 1846. They crossed the Mississippi River and waited for all those who would be leaving to join them. The others had crossed the Mississippi by summer, when they traveled to Nebraska and set up a Winter Quarters. The next spring, groups began leaving Winter Quarters and arrived in the Great Salt Lake Valley beginning in July 1847.

After the first group arrived, the trail was travelled nearly constantly (excepting a few winter months) for 21 years. These groups came from many areas of the world and began at many starting points. The best time to begin on the trail was March through May, any later than that and they risked being caught in early winter storms on the plains.