Due to the short growth duration of summer maize, which is planted after winter wheat harvest to form the annual double cropping system in the North China Plain (NCP), maize yield is significantly affected by weather conditions. This study examined the seasonal yield variation and the effects of weather factors on yield and yield components of summer maize under full irrigation (FI) and deficit irrigation (DI) conditions during 2008 to 2016 using a local popular cultivar 'Zhengdan 958'. In addition, eight cultivars in 2010 to 2012 and 16 cultivars in 2013 to 2016 were tested to examine crop responses to weather factors. Results indicated that seasonal yield variation was up to 47% of the average yield of the nine seasons. Grain kernel weight was the main yield component affecting annual yield variation under FI. Further analysis showed that daily maximum temperature (Tmax), diurnal temperature range (DTR), and daily reference evapotranspiration (ET0) were each positively related to grain kernel weight from blister stage to maturity. Results from the cultivar tests showed that the yield difference among the cultivars was up to 35% of the average grain yield. Selecting cultivars with higher yield potential in each season could decrease the seasonal yield variation up to 32%. Cultivars with smaller leaf angle of upper leaves, higher final aboveground biomass, higher harvest index, and an earlier tasseling date would likely lead to more stable, higher yields for short season maize in the NCP.