You could use any thermometer you trust is accurate as the reference. I suspect the mercury or alcohol thermometers used for checking for body temperature would work, the digital ones (at least the ones I have) don’t start working until the temperature is in the mid 90’s so they may not be the best. Choice.
What are you using for reference?
Weber scientific traceable t shaped thermometer item# 3516-11
How do I calibrate the temp without that fancy tool you have?
You could use any thermometer you trust is accurate as the reference. I suspect the mercury or alcohol thermometers used for checking for body temperature would work, the digital ones (at least the ones I have) don’t start working until the temperature is in the mid 90’s so they may not be the best. Choice.