When it rains in Pompeii, the archaeological site can become quite slippery and muddy, but you can still have a productive day by focusing on sheltered locations. Your first stop should be the Antiquarium of Pompeii, an indoor museum near the Porta Marina entrance that houses incredible artifacts and casts of victims. Several of the larger "Domus" (houses) have modern protective roofs, such as the Villa of the Mysteries and the House of the Menander, which allow you to view frescoes while staying dry. If the rain is torrential, many travelers take the Circumvesuviana train (just 30-40 minutes) to the National Archaeological Museum of Naples (MANN), where the most famous original mosaics and statues from Pompeii are kept in a climate-controlled indoor environment. In 2026, it is highly recommended to wear non-slip shoes, as the ancient Roman stones become extremely treacherous when wet. Carrying a compact umbrella is better than a poncho, as it allows you to easily move in and out of the smaller, cramped indoor rooms of the ancient houses.