Glass thermometer calibration has high environmental requirements, as environmental factors can directly affect the accuracy of calibration results. Below are the environmental requirements to consider during calibration:

1. Temperature Stability
   The calibration environment should maintain a constant temperature to avoid fluctuations. For example, when calibrating using the ice point method, the ambient temperature should be close to 0°C; when using the boiling point method, it should be close to 100°C.

2. Humidity Control
   High humidity may cause condensation on the thermometer's surface, affecting reading accuracy. Therefore, the calibration environment should maintain an appropriate humidity level.

3. Vibration-Free
   Vibrations may cause the thermometer's liquid column to fluctuate, affecting reading stability. The calibration environment should avoid mechanical vibrations or external disturbances.

4. Lighting Conditions
   Strong light may make it difficult to observe thermometer readings, especially for alcohol thermometers. It is recommended to use soft lighting during calibration.