Accessories for a power switch? That's right!
If you're looking to have Z-Wave control outside or extend the Z-Wave signal for any outdoor devices, you could try the ZEN15 Power Switch in a weatherproof box.
While it's not specifically rated for outdoor use, users have been able to successfully use the Power Switch outdoors with weatherproof boxes like the SockItBox: http://www.sockitbox.com/
You may also need a waterproof cord to extend to the box as well depending on your set-up. Just make sure that the temperatures won't drop below the ZEN15's operating temperature [14°-104°F (-10°- 40°C)] before installing it outdoors.
Let us know if you have any questions, we'll be happy to help!