SHANGHAI'S low is expected to fall below zero degrees Celsius during the weekend.
The cold comes as the city entered its meteorological winter last Sunday, forecasters said.
After a moderate, sunny day today with a low of 5 degrees Celsius and a high of 13, tomorrow is forecast to see the low drop to minus 2 degrees and a high of 10 downtown.
The mercury is expected to fall to minus 1 degree on Sunday, with the high rising only to 6 degrees.
The suburbs should be even colder, according to the Shanghai observatory.
The weekend is expected to be partly cloudy with drizzles to follow next week, the observatory said.
Shanghai has been chilly this week, with temperatures reaching 2.8 degrees Celsius yesterday morning. The readings in the suburbs were even lower and all below zero.
The observatory last night announced the beginning of the meteorological winter this past Sunday as Shanghai's average temperature had been below 10 degrees since.
Zoo keeping its animals warm
The Shanghai Zoo has taken a number of measures to protect animals from the cold.
Chimpanzees and giraffes, some of the most vulnerable to chills, have been kept indoors with oil heaters. The temperature is set at 20 to 25 degrees.
Stoves and warmers helping squirrel monkeys and ring-tailed lemurs from temperate zones keep warm were set up at their pavilions before the cold front arrived.
When there is abundant sunshine, the animals are allowed to access outdoor areas.
The traditional Chinese medicine theory of nourishing with food to strengthen yang energy in winter is also applied to animals at the zoo to help them keep healthy, officials joked.
The amount of food is increased and food rich in nutrition and calories is added into the recipe. Some herbivorous animals like takin are fed with forage rich in vitamins and trace elements, while African lions and cheetahs are fed with more high-calorie beef and mutton.
Giant pandas and golden monkeys are fed milk, eggs, peanuts and red dates to help them through the winter.