Delayed selfing is regarded as a reproductive adaptability, because it apparently ensures seed production when pollinators are scarce, yet it allows outcrossing to predominate when they are abundant. Delayed self-pollination by curvature of stigma-lobes occurs in flowers of Kosteletzkya virginica, when pollinators are scarce or absent. Based on the observation data of delayed self-pollination of K.virginica growing in the naturalized population in the Yancheng tideland, Jiangsu province, China and climate data from 2002 to 2005, and the observation data of different stop types of stigma lobes within-flowers in 2005, percentages of flowers undergoing delayed self-pollination and different stop types of stigma lobes were analyzed, and comparing their differences between fine and inclement weather conditions. The conclusions showed that percentages of flowers undergoing delayed self-pollination during 2002-2005 were 13.50%±1.62%、14.39%±1.50%,14.05%±1.82% and 13.47%±1.51%, respectively, and there was not significant difference among different years (F_{(3, 189)} = 6.128, P = 0.085). The percentage of flowers displaying delayed self-pollination to all flowers on cloudy / rain days (22.11%±0.94%) was significant higher than that of sunny days (5.43%±0.43%) (F = 8009.780, P < 0.001). Percentage of stigma lobes of curve stop by floral parts movement on sunny days (18.64%±1.61%) was significant lower than on cloudy / rain days (70.58%±2.06%) (U = 0.000, W = 465.000, P <0.001). Percentage of flowers of K. virginica displaying delayed self-pollination is directly respond to the weather conditions influencing pollinators environments, this provides the potential for testing the reproduction assurance hypothesis in the level of individuals or flowers.