It is the cold souls 

who need the most warm weather 

  The cold souls among mankind. The sullen. Those who seem unlovable.
  Oh, yes, the unlovable. The unlovable are the ones we need to love the most. Think of how a person who is struck, strikes back. It is nature. If someone feels rejected, they become angry. They lash out in return.
  In a world that dreams of peace, it is the hurt, the hardened, who commit so many crimes. It is the hurt, the hardened, who often beat their spouses and children. You extend them love, and who knows the peace you bring into this world.
  Every human being needs to be loved. It is the fuel that gives them life. Those rejected by society, and those rejected by their peers are left without that food which gives life meaning. And, with no reason to live, they become a flame of fire, a fireball that torches humanity before flaming out in its own death. I do not know, for certain, why a share of mass murderers take their own lives, but I do wonder if this is it: They have been so rejected by society that they lash out in anger at the world. But, then, having no reason to live, they also take their own lives.