What is the difference between the hottest and coldest temperatures from the cities listed? Use the temperatures from part a) of the question.

The temperatures are:
City F: $-10^\circ$C
City E: $-8^\circ$C
City A: $2^\circ$C
City B: $8^\circ$C

The hottest temperature is $8^\circ$C (City B).
The coldest temperature is $-10^\circ$C (City F).

Difference = Hottest temperature $-$ Coldest temperature

$$\text{Difference} = 8^\circ\text{C} - (-10^\circ\text{C})$$ $$\text{Difference} = 8^\circ\text{C} + 10^\circ\text{C}$$ $$\text{Difference} = 18^\circ\text{C}$$

The difference in temperatures between the hottest city and the coldest city is $\boxed{18^\circ\text{C}}$.