By evaluating of the ability to predict the 2m temperature and relative humidity, 10m wind direction, and wind speed, as well as T639 model products of two precipitation processes in Inner Mongolia, it is concluded: the forecast accuracy of temperature and relative humidity is better than those of the wind direction and wind speed; the errors of temperature and relative humidity forecast are smaller systematically; the probability of larger wind speed forecast error is high relatively; the precipitation forecast accuracy decreases with the rainfall intensity; in terms of the light rain, the missing alarm rate is lower than the false alarm rate, and the deviations of both overestimated and underestimated rainfall intensity are about the same; the deviations of wind direction are along the clockwise with the angle less than 45°; the temperature deviation is smaller in general, and the distribution of the relative humidity forecast deviation is “＋ － ＋ －” from west to East. The rain falling area is larger for light and moderate rains, and smaller for others. The predicted Lake Baikal cold vortex strength is stronger; the West Pacific subtropical high is weaker; and its influence range is farther north and west.