Does anyone ever wonder if weather can have affect an out come of wiccan spells?

The reason why spells are often timed to other events is because it increases or reinforces the layers of symbolism being used to speak to your unconscious self about your conscious desires. The magic lies solely in you and your ability to effectively communicate with yourself. Visualizations and archetypal imagery are effective psychological tools, but they have no power in and of themselves. So the answer to your question is that the weather will affect your spell work only as much as you believe that it will