Rock can be tied or glued to a rope or tied up in nylon netting to hang outside. You can add googly eyes to the rock also. Add the following poem.
I'm a weather-wise rock.
If I'm wet, it's raining.
If I'm moving, it's windy.
If I'm white, it's snowing.
If I'm icy, it's sleeting
If I'm bouncing, it's hailing.
If I'm hot and dry, it's sunny.
If you can't see me, it's foggy.
If I'm gone, you've been ripped off!