weather / whether
The state of the atmosphere vs. the conjunction that introduces alternatives.
Weather is the state of the atmosphere at a place and time—temperature, wind, rain, snow, heat, cold. Whether introduces alternatives or an indirect yes-or-no question: whether the load left, whether to wait or go. Use weather for atmospheric conditions; use whether for the choice.
Examples
Use The weather delayed the load.
Use Tell me whether the load left.
Avoid Tell me weather the load left.