I would say here that bad weather is not the absence of good, but rather the currently less desirable of the available options to the specific individual or group.
The same rain or snow may be bad weather to one group, much needed and desired by another group. Even weather classified as natural disasters are part of the natural order and serve a pupose. It simply may not be a purpose desired by humans.
Why is there evil? Why is there suffering? What is the purpose of life?
Why is there evil?
Primarily because we are human and capable of acting in ways that are not conducive to the survival or optimal functioning of our communities. Evil appears to be a specifically human experience (ever seen Eddie Izzard’s routine on what an evil giraffe might be like? Very funny).
I am not 100% convinced that there are evil entities that exist in the spiritual realm, though I am convinced that there are forces we should not mess with. There are many things that, while not inherently inimical to humanity, are also not inherently well-disposed. This is one reason I stay as far away as possible from things related to ceremonial magic—bindings, spells designed to control or change others, etc. To believe that we can compel or control such forces is a form of hubris to me, and strictly forbidden in my understanding of my religion.
It is important also to know that Hellenic religion has no concept of imitatio dei. We are not to consider that the acts of the Gods are standards for our own behavior, as that is also a form of hubris. Hubris is believing or acting as if we are the equal (or even worse) superior of the Gods. Inscribed at Delphi is “know thyself” along with “nothing in excess.” “Know thyself” is to know that you are human, not divine, to know your place in the universe. The Gods are the Gods, humans are humans.
Personally, I am not even comfortable with the Wiccan practice of invoking, summoning or dismissing forces during a circle, as it smacks of hubris to me. Inviting is one thing, believing we have the power within ourselves to compel or control is quite another and very dangerous in my book.
Why is there suffering?
Because we live and there are things that are part of the natural order that we find painful and undesirable. It is simply part of the human condition that disease, accidents, disappointments, tragedies and death will occur. It is usually unlikely to be the result of the specific will of the Gods (though I suppose specific instances may exist where such could be possible). Overall, the Gods do not appear to be interested in micromanaging our lives.
As I have heard—“when you hear hoofbeats outside the window, expect to see horses, not zebra.”
What is the purpose of life?
To live the best life we can. For me, best includes behaving in a responsible manner that helps to maximize the survival and peace of the community long term, charity and compassion for others and doing my best to live in harmony with all the other aspects of the natural world, not just humanity.