The weather is best in Naples & on the Amalfi Coast in the Spring or Fall, although in the winter it could be an ideal destination for a weekend as the lively Christmas markets and clear visibility make it more desirable than most Italian cities. Especially, considering it's milder winter climate.
But, remember in the winter months with the shorter days you'll have to limit the range of your sightseeing to make the most of your days. In the winter, you could do a half-day tour of Pompeii or the Amalfi Coast, but you wouldn't have time to visit both in daylight hours.
The weather in Naples & along the Amalfi Coast in the summer can be very hot and humid as well, which also limits visibility for those wanting to trek up to the summit of Mt. Vesuvius. It's also a time when hordes domestic tourists descend on to the Amalfi Coast and the Islands of the Bay of Naples for their annual vacation.With many businesses also being closed during this period we recommend another time of year to visit Naples & the Amalfi Coast when both the weather and temperament of the locals is less oppressive.
The spring weather, along with the flowers blossoming is probably the ideal time of the year to visit Naples & the Amalfi Coast. The heat is not oppressive and the number of tourists visiting the area don't detract too much from Naples and the beauty of the Amalfi Coast. In the Fall, from the second week of September you'll also discover a more calmer city, and along the Amalfi coast the lemon and olive trees provide the colour and ambience that typify this time of year in Naples & along the neighbouring Amalfi Coast.