A weather-based irrigation controller uses data from weather stations to adjust watering schedules based on environmental conditions such as temperature, humidity, and rainfall. It does not directly measure soil moisture levels.
On the other hand, a soil moisture sensor measures the actual moisture content in the soil and provides real-time data on when and how much water is needed for plants. It directly measures the moisture levels in the root zone of plants, allowing for more precise and efficient irrigation.
In summary, a weather-based irrigation controller uses weather data to adjust watering schedules, while a soil moisture sensor measures actual soil moisture levels to determine irrigation needs.