During the 16th century many people believed that washing oneself opened the pores to let in disease. So most people did not take baths very often. Needless to say that people had odors.
That would not be pleasant, especially at a wedding. To take the
bad odor away, brides started to carry sweet-smelling flowers in
a bouquet-- a tradition that has lasted even when sanitary customs have changed.
Generally, people did their "spring cleaning"-- a name for a yearly bath in May or June. Since people were cleaner in June, it was a good time for a wedding. Thus the tradition of June weddings took hold.