The latest weather in Yanzhou

A, 3 1 The upper air pressure is low, which is mainly affected by warm air, which does not meet the meaning of the question;

B, 1 The daytime temperature is low, which is correct, mainly due to the strong weakening effect of the atmosphere and the great influence of cold air;

C, 1 The wind is strong, mainly because of the cold front crossing the border, so it does not meet the meaning of the question;

The low temperature on the night of day D and day 2 is mainly due to the weak atmospheric inverse radiation.

Therefore, choose: B.