Grain chalkiness is a major cause of low quality in many rice-producing areas of the world. Though, little is known about the relationship between different sowing dates and the characters of grain chalkiness for grain quality improvement in rice. In this study, the grain chalkiness characters of twenty-one and seven rice varieties were investigated across four and six sowing dates in two years. The results showed a wide range variation of grain chalkiness in diverse varieties across sowing dates, and a positive correlation between chalkiness rate (CR) and the temperature during grain filling phase for all of the varieties. Slight correlation between grain chalkiness area (CA) and the temperature during grain filling phase was also observed for the test varieties in 2015. The chalkiness characters of some varieties were dramatically sensitive to heading dates, while other varieties had a low level of CA and CR across different sowing dates. Improvement of grain chalkiness could be realized by selecting optimum sowing dates in rice production and varieties with low and stable chalkiness could be considered as the elite parental lines in the artificial breeding of the new rice varieties. Therefore, our results have paved the way for the improvement of grain chalkiness in rice.