The same rules that apply to standard crane operation apply here; only an experienced and qualified appointed person should attempt to operate a crane.
This individual will be able to competently complete lifting operations and suspend them safely if conditions change.
If the site manager has determined that weather conditions are too unsafe to continue lifting, no person should attempt to operate a crane.
A fog that drastically reduces visibility, heavy rain shifting the ground below, or lightning could have forced their decision.
However, sometimes conditions are more extreme than usual without being determined as dangerous enough to halt lifting, such as high winds below 20mph.