Is it still hot in September in southern China? Such as Ningbo

Yes, it is still hot in September in Ningbo. The average daily temperature is between 2 1-28℃, but the maximum daily temperature is basically above 30℃, but it will be cooler than summer sooner or later. So generally speaking, except at the end of September, it is sometimes cold, so just wear short sleeves.

Moreover, according to meteorological records, September is a rainy month in Ningbo, and the average rainfall is only slightly less than that in June. Northerners will still be surprised that there is so much rain in autumn.