Naples has a borderline Mediterranean (Csa) and humid subtropical climate (Cfa) in the Köppen climate classification, since only one summer month has less than 30 millimetres (1.18 in) of rainfall, preventing it from being classified as solely Mediterranean or humid subtropical. The climate and fertility of the Gulf of Naples made the region famous during Roman times, when emperors such as Claudius and Tiberius holidayed near the city. The climate is a crossover between maritime and continental features, as typical of peninsular Italy. Maritime features moderate the winters, but summers are quite similar to inland areas much further north in the country. The continental influence still ensures summer highs averaging near 30 °C (86 °F), and Naples falls within the subtropical climate range with summer daily means of 23 °C (73 °F).