Daily precipitation data from 447 stations in eastern China were used to discuss the spatio-temporal characteristics of different grades of precipitation during the period of 1980-2013. Correlations between light rain and lower tropospheric temperature (LTT), lower tropospheric water vapor content (LTW), and lower tropospheric relative humidity (LTRH) were subjected to EOF and composite analyses. The contributions of warming and the variation in relative humidity to the decrease in light rain were clarified by using the Clausius-Clapeyron equation. The characteristics of the reduction in light rain over the Yangtze River Delta were also analyzed on the basis of daily visibility data. The following results were obtained: (1) Annual mean precipitation days and precipitation amount over eastern China declined with increasing latitude, and light rain days (LRD) provided the major contribution to all rainfall days, and accounted for 71.84% of all rainfall days. Different grades of rain, except for storms, all tended to decrease, and LRD and light rain amount (LRA) distinctly decreased at the rates of -3.37 d (10 a)^-1 and -6.52 mm (10 a)^-1, respectively. The first mode of EOF for LRD showed the reduction of LRD over the whole study region, whereas the second mode showed distinct spatial differences. (2) The reduction in light rain was accompanied by lower tropospheric warming. LTT increased at the rate of 0.32 K (10 a)^-1. By contrast, LTW slightly decreased. The positive correlations of the variation in light rain with LTRH indicated that the spatial characteristic of LTRH was similar to that of light rain revealed by EOF analysis. The results of composite analysis suggested that light rain was low (high) in the year of high (low) LTT, and high (low) in the year of high (low) LTRH and high (low) LTW. (3) Calculations obtained by using the Clausius-Clapeyron equation and the relative humidity equations revealed that the saturation vapor content increased by 6% K^-1 to 7% K^-1 as a result of lower tropospheric warming, which induced the distinct decrease in the LTRH given the negligible change in lower tropospheric specific humidity and ultimately reduced light rain. The effects of LTT and lower tropospheric specific humidity on the changes in light rain suggested that the 4.83% reduction in light rain was caused by LTT only, whereas the 1.91% reduction in light rain was caused by lower tropospheric specific humidity only. (4) Although annual mean LRA and LRDs were considerably low in regions with low visibility, the long-term reduction in light rain induced by the decrease in LTRH was attributed to lower tropospheric warming.