 Let's see how to find the wet bulb potential temperature on this QT. The first step is to find the LCL. Once we find the LCL, then we have a saturated air parcel and its temperature is the wet bulb temperature. To find the wet bulb potential temperature, we simply follow the moist adiabat down to a pressure of 1,000 millibar. We see that the wet bulb potential temperature is about 19 C, while the potential temperature is about 34 C.