The climate is humid, close to maritime, with a moderately warm summer and a rather long moderately cold winter.
The average winter temperature is -8°С, the average summer temperature is +18°С.
In dry hot weather the temperature may rise to +25°С/+30°С. The temperature
drops dramaticaly in winter, reaching -25°С/-30°С. Precipitation reaches 634 mm
per year. The Neva River is the city's main waterway. The name of the river derives from the ancient name of Lake Ladoga, the Neva where it begins. The Neva is 74 kilometers long, flowing 32 kilometers within the city boundaries. The average width of the Neva within the city is 600 meters, depth - up to 24 meters. In the delta, the Neva splits into three main branches: the Bolshaya Neva, the Malaya Neva and the Bolshaya Nevka. The city is located on the hanks of the Neva and about 100 rivers, canals and straits. Water constitutes 1/l0th of the area of the city. The abundance of islands has led to the construction of a multitude of bridges. Of these, there are 308 within the city proper, and 534 if suburbs are included. Twenty two of the bridges are drawbridges. The total length of all the bridges is about 16 kilometers. The longest bridge across the Neva is the Alexander Nevsky Bridge (909 meters), and the widest bridge is the Siniy Bridge on the Moika River (99.5 meters).
Saint Petersburg stands on the 47 islands of the Neva Delta. The biggest islands are Vasilievsky and Petrogradsky. Floods occur frequently in the city. Most often they happen during the autumn due to strong westerly winds. In the history of the city the Neva has risen above the ordinary level more than 300 times. The biggest flood was on November 7th 1824 when the water rose 4.1 meters above the ordinary level.
The population of St. Petersburg is 4,715,7 as of the beginning of 2001.