If the weather permits, they will go out for a journey this weekend.= Weather permitting, they will go out for a trip this weekend. = With the weather permitting, they will go out for travel this weekend. = Supposing / Suppose / Providing / Provide (that) the weather permits, they will go travelling this weekend.= On condition that the weather permits, they will go on a journey / trip this weekend.= Weather permitting, they will take / make a trip / journey this weekend.