Something expected is likely to happen: it's probable. During winter, snow is expected.
When you expect something, you anticipate that it will happen. As people age, they expect some grey hair. Things described as expected are things people know will probably happen. For football players, many injuries are expected. If you have a baby, many changes in your life are expected. For example, it’s expected that the baby will often cry, causing the parents to lose sleep. Expected things are the opposite of surprising things. No one is surprised by an expected event.