The weather forecast in Lianjiang county is 30 days.

Special topic: application problem.

Analysis: subtract the temperature of Beijing from the temperature of Lianjiang, and then calculate it according to the fact that subtracting a number is equal to adding the reciprocal of this number.

Judging from the meaning of the question,13-(-6) = "13"+6 =19.

Comments: This topic mainly investigates the algorithm of rational number subtraction, and mastering the algorithm skillfully is the key to solving the problem.