If you go in the summer, an umbrella is great to have as there is very little shade. There is a wonderful, modern archaeological museum, with some of the most important finds of the Greek and Etruscan civilizations, including the 5th century Tomba del Tuffatore (Tomb of the Diver). I like to step outside onto the east patio and take a breather while looking at the mountains in the distance.
If you visit in the summer, they have what are known as “night trails,” where you can roam the ruins by moonlight. The temples are also lit up and there are musical performances. In mid-August the Paestum Danza, Musica, Teatro performing arts series takes place.
Italians love their festivals – I truly believe there is one held every day – so whatever time of year you visit, there is one to experience. Nearby ones include artichoke and chestnut festivals and further afield, in Controne, there is the yearly Festival del Fagiolo, when nearly 30,000 people descend on the village of 900.
Paestum itself is not very large and it is easy to walk the entire area. It is worth hiring a local car or guide with a car (both very reasonable) to visit more of the surrounding area.