Ions move faster as they get warmer, resulting in high conductivity.
The conductivity of the ions in water depends upon the temperature. Although there are various factors that cause this effect, the major reason comes from the fact that ions move around faster as they get warmer. The moment when the same number of ions are starting to move faster, the apparent conductivity increases. As tap and other natural waters have many different ions in them, conductivity systems sometimes respond nonlinearly with temperature changes. For this reason, we have built-in a conductivity meter that simultaneously measures the temperature of the water.