In order to obtain a complete picture of the water balance, various other meteorological parameters are measured in a number of places in Flanders, in addition to precipitation and precipitation intensity. These measurement data are used to calculate the potential evapotranspiration (pET), which is the maximum amount of soil moisture that plants can evaporate or that can evaporate directly from the soil.

The potential evapotranspiration is calculated using the Pennman-Montheith formula. For this calculation, the temperature at different heights above the ground, the air pressure, the relative humidity, the wind direction and speed, the irradiation flux from the sun, and the ground heat flux are measured. In addition to the potential evapotranspiration, the dew point temperature is also calculated from this data. The soil temperature is also measured in a number of places.