Data of observations over precipitation in a big city and in a countryside for a 20-year period are analyzed. Occurrence (the number of cases) and the number of days with precipitation, as well as precipitation amount, intensity, and duration are determined. Influence of a city on the precipitation field is found to be less significant than its influence on the fogs and hazes. The exception is heavy precipitation, occurrence and duration of which in a city are much less than in the countryside. Precipitation characteristics at day- and night-time are close to each other. Dynamic factors, first of all, vertical motions of the synoptic scales, play the decisive role in the formation of precipitation fields. The role of thermal factors (change of the vertical temperature lapse rate under influence of the solar radiation influx) in the formation of precipitation does not exceed 2-5%.