Bests & Worsts Reviews from Amazon

I bought this because I live by a river and I wanted to confirm the true temperature outside of my home, compared to what they were reporting online. This way I would know when was the best time to open the windows and draw in the outside air. Unfortunately the reading is 4+ degrees higher than what it should be. When I suspected the readings were inaccurate, I brought the outside module inside and placed it side-by-side of the main unit. After an hour, and throughout the next day, the main indoor module always read exactly the same as my AC thermostat, while the sensor made to be outside, would always read 4+ degrees higher. And today the outside unit read 7 degrees higher than what they reported online. And NO this unit is NOT in the sun, it is under the patio with the unit's vent unobstructed. This is garbage, waste of $25. How can this thing have so many good reviews??