I wouldn't plan anything from June 15th on, some places have multiple orientations (one for medicine, one for psych, one for Human Resources, and many others) This is likely true for all specialties.
Generally, all residencies start July 1. Each institution has their own (or lack of) orientation usually toward the end of June that lasts typically between 3 days and 2 weeks. Call the institution you're going to in order to get the details. It's a reasonable question since you're trying to plan your summer.