Are you preparing your suitcase and don’t know what carry with you?
The climate is mild from spring until October, then according to season you can carry most suitable clothes.
See these links for information about seasons and weather:
When visit Positano?
Weather in Positano

Before enjoying your holiday in Positano you need to know how to get there, so I suggest to have a look here:
Arrive to Positano from Napoli
Arrive to Positano from Salerno

Once in Positano you will organize your days, so click on the links below to find out what to see and do:
The 10 best attractions in Positano
Itinerari guidati

Remember your camera, because there will be many landscapes to capture for keep your memories alive.