The waterproof version of DS18B20 temperature sensor is useful when you need to measure temperature from some distance or in wet conditions. While the sensor is good up to 125C the cable is encapsulated in PVC so it suggested to measure under 100C. Since it is digital, the user do not face signal degradation over long distances. The DS18B20 provides 9 to 12-bit (configurable) temperature readings over a 1-Wire interface, so that only one wire (and ground) needs to be connected from a central microprocessor with 3 to 5.5V voltage supply. Because each DS18B20 contains a unique silicon serial number, multiple DS18B20s can exist on the same 1-Wire bus. This allows for placing temperature sensors in many different places. Applications where this feature is useful include HVAC environmental controls, sensing temperatures inside buildings, equipment or machinery, and process monitoring and control.
This DS18B20 based probe is very handy when it comes to measuring temperature of objects in wet condition. Digital output of DS18B20 eliminates the possibility of signal loss or noise and thus it can be used to measure temperature of objects which are at distance from the controller/processing unit by increasing the length of wire.