This is camp cooking temp that tip is handy to know.
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.
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.
Camp Fire Temperature Estimation Times:
5 seconds = low
4 seconds = medium
3 seconds = medium-high
2 seconds = high
This is an awesome prepper skill to have, it works great with outdoor baking as well as other cooking skills.
I have used it to cook steak over coals for a really impressive and testosterone fueled dinner. This skill really separates the woodsmen from the campers.
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