The historical city is divided into six areas or "sestiere" (while the whole comune (municipality) is divided into 6 boroughs of which one is composed of all 6 sestiere). These are Cannaregio, San Polo, Dorsoduro (including the Giudecca and Isola Sacca Fisola), Santa Croce, San Marco (including San Giorgio Maggiore) and Castello (including San Pietro di Castello and Sant'Elena). Each sestiere was administered by a procurator and his staff. Nowadays each sestiere is a statistic and historical area without any degree of autonomy.
These districts consist of parishes – initially seventy in 1033, but reduced under Napoleon and now numbering just thirty-eight. These parishes predate the sestieri, which were created in about 1170.
Other islands of the Venetian Lagoon do not form part of any of the sestieri, having historically enjoyed a considerable degree of autonomy.
Each sestiere has its own house numbering system. Each house has a unique number in the district, from one to several thousand, generally numbered from one corner of the area to another, but not usually in a readily understandable manner.
Climate
According to the Köppen climate classification, Venice has a Humid subtropical climate (Cfa), with cool winters and very warm summers. The 24-hour average in January is 3.3 °C (37.9 °F), and for July this figure is 23.0 °C (73.4 °F). Precipitation is spread relatively evenly throughout the year, and averages 748 millimetres (29.4 in).