Floods in Venice are not so rare. But when the flood occurs in May, it is strange and when the water level rises above 100 cm in May, it is almost unprecedented. May 18, 2019, the water was very high, namely 112 cm above the norm.
According to tide records from 1872 to today, such an event occurred only 4 times in May: in 1984, 1997 and twice in 2013.
110 centimeters involves the flooding of 12% of the surface of the historical center.
According to the data, in May there were only 4 other floods with values of more than 110 centimeters:
05.21.1984, maximum 118 cm
06/05/1997, maximum 126 centimeters (49.6 inches)
05/16/2013, a maximum of 110 cm (43.3 inches)
05.23.2013, a maximum of 112 cm (44.1 inches)