The actual groundwater temperature, before being exposed to ambient air at the surface, can make a substantial difference in the water the Freeze Miser will release, all other factors being the same, i.e. Air temperature, wind, etc. With groundwater temperature of 55°F – 65°F the Freeze Miser will release less water than if groundwater is 45°F. It is possible that if the ambient air temperature is above 37°F/3°C, the Freeze Miser may still release water because the water it is sensing is less than 37°F/3°C.