Cusps are astrological terms used to describe the days when the sun transitions between two zodiac signs. These days are typically considered to be the 1st and 2nd day of each month, but depending on the year and the speed at which the Earth travels a tiny minority may be born in the cusp of one sign and another day of the month. Cusp positions are extremely rare, and someone born a day or two on either side is not considered to have any traits from the "cusp" sign. There is no scientific evidence to suggest that people born on cusps have traits of both zodiac signs. In fact, studies have shown that there is no correlation between birth dates and personality traits.