Recently, the use of existing measurements from a commercial wireless communication system as an opportunistic sensors for environmental monitoring has been proposed. In particular, measurements of the received signal level (RSL) in the backhaul communication microwave network (CMN) of cellular systems are considered as opportunistic sensors. We suggest to refer to this application as an example to an IoT, since it naturally shares many of IoT’s features. Recent results have demonstrated the use of the suggested technique for estimating and mapping of rain, as well as of monitoring other-than-rain phenomena, such as: snow and sleet, moisture, for and dew. While results have been obtained on a national level, I will discuss the challenge in expanding this approach to the global arena.