uRADMonitor should be mounted outside, but not directly exposed to rain or sun. A covered spot with some shadow in the free air is ideal (under the balcony, on a wall with protection from the Sun, etc). If the unit should be placed in a location where rain is likely to reach, consider protecting the uRADMonitor device with a plastic case. Should water get inside the unit, the device would be compromised. See the pictures below:

Using a simple plastic bag (or several for multi-layer), we can protect the unit by mounting it inside the bag with the wires exiting on the bottom. The complete guide, can be found here.