Traditional Culture Encyclopedia - Weather forecast - The following table shows the weather conditions in Shanghai from April 4 to 7, 20 13+65438. (Maximum temperature during the day and minimum temperature at night in℃)) Date 1.

The following table shows the weather conditions in Shanghai from April 4 to 7, 20 13+65438. (Maximum temperature during the day and minimum temperature at night in℃)) Date 1.

Directly from the weather conditions and temperature changes in the table, the affected weather system is a cold front, so the temperature is lower after the cold front is controlled by the cold air mass; And the snow covers the ground, and the reflectivity of the snow surface is high, which leads to less solar radiation absorbed by the ground and lower temperature.

Therefore, choose: B.