We investigated spatial and temporal variations in adverse meteorological conditions during the maize growing season in Southwest China. Datasets covered observed phenological data from 27 agro- meteorological stations(1981- 2010)and daily meteorological data from 66 meteorological stations(1961- 2010). These data were used to calculate agro- meteorological indices such as successive overcast weather,high- temperature day,low- temperature day,water surplus and deficit index,indicating adverse meteorological conditions in the most recent 50 years. We found that successive overcast weather occurred frequently from emergence to seventh-leaf and from seventh- leaf to heading,and the frequency increased by 12% and 15%,respectively after climate warming. A total of 11% and 14% of stations decreased during these two periods. Heat stress mainly occurred during the period from milking ripeness to maturity,which mostly centered in northeast of Southwest China. The number of days with heat stress decreased by 2.5 days after climate warming,with 23% of stations decreasing. Low- temperature days occurred during the whole growing season,and the number of days with cold stress decreased by 2.2 days after climate warming,especially during from seventh- leaf to jointing when 56% of stations decreased. Hightemperature days mainly occurred from sowing to jointing,and the frequency of light water deficit and medium water deficit increased by 6% and 7%,respectively. The water surplus happened through the maize growing season,but it was always mild. The frequency of light water surplus increased by 15% after climate warming,with 21% and 11% of stations increasing significantly during sowing-jointing and grain filling-maturity,respectively. The decrease in heat stress and cold stress has a good impact on the growth of spring maize,however,the increase in cloudy days and water surplus/deficit may decrease quality and yield.