Tomb sweepers are warned to brace for a rainy dongzhi, or winter solstice, tomorrow, although temperatures are forecast to be relatively warm for this time of year.
Highs are expected to fluctuate between 15 and 17 degrees Celsius today and tomorrow, after reaching 17.6 degrees yesterday from a low of 12, according to the meteorological bureau.
Rains are expected today and tomorrow for dongzhi, a time for people to pay their respects to the dead by visiting and tidying tombs.
Pollutants are again being blown in from the north and are expected to cause light pollution on Friday.
Between December 1 and 18, Shanghai had eight polluted days, including three classified as moderate, due to northerly winds.
Rains are forecast for the weekend and residents are advised to carry an umbrella when going out for Christmas celebrations.
The weather bureau said that it's not unusual for temperatures to reach 16 to 17 degrees in winter.
The warmest mid-December day on record was December 16, 1921, when the mercury hit 24.1 degrees.