The temperature diagram is divided into three ranges:
Green Tea: 65°C-167°C/ 149°180°
Black Tea: up to 95°C/ 203°
Herbal Tea: up to 90°C/ 194°
At CiTea, we find it easiest to use an electric kettle to heat the water to the boiling point, then insert the water in the mug or pot, put the stem of the thermometer into the mug or pot between the lid and rim, and monitor the temperature until it lowers to the desired level.