This is camp fire temperature estimation tip is handy to know.
Until you do this enough to memorize, I would laminate an index card with the chart below and stick in somewhere with your camping/bugout equipment
If you have ever tried to manipulated something in a campfire fire, you know that the hotter the fire the less time you can stand to have your hands near it.
This means that you can learn to judge the temperature of a fire by knowing how much heat a common person can stand.
Please use some common sense with this, but if you cautiously hold your hand, palm side down, over the fire at cooking height and count the number of seconds you can hold that position and you will have an indicator of how hot the fire temperature is:
5 seconds = low
4 seconds = medium
3 seconds = medium-high
2 seconds = high