Friday is the third Friday the 13th of 2015. 

The first two came in February and March.

Historians have several possible explanations for why superstitions evolved around Fridays and the number 13.

Other experts have weighed in on the theories as well.

Connecticut psychotherapist Maud Purcell says we all feel out of control in life often, and it's a natural thing for people to look for something that can help them understand why things happen the way they do.

Purcell says that throughout time, people have found patterns and assigned meanings to them -- often signs or dates -- then rearranged their lives accordingly.

"If we have a sense that something bad might happen and we prepare for it, it tends to give us a sense of control -- real or perceived," Purcell says. "And Friday the 13th, for many people, serves that purpose."

The next time three Friday the 13ths will occur during the same calendar year is 2026.