An individuals' temperature will not read higher based on wearing a darker colored cap or clothing. The temperature scanned is the skin. The camera is using the face detection analytic to detect a human face then apply the algorithm built into the camera to display a temperature that is read from the epidermis of the forehead, or if it is a profile picture captured, the skin around the earhole is used.
If you're wearing a mask, glasses, hood, hat, or all combined, if those two focal points aren't blocked, then the camera can give a temperature reading.
Depending on the type of hat, for example, a forwards facing baseball cap pulled down entirely over the forehead can cause an individual not to be scanned. Another factor that could affect the scan is how the camera is mounted. The cameras must not be mounted higher than 8-feet. If the camera is wall-mounted and facing on a downward angle where a hat or hardhat is blocking the forehead, a solution would be to mount the cameras on a tripod to get a more direct shot.
Please watch the scenario video here for more info on this.
As for individuals who have been out in the extreme heat or cold for an extended time you may want to wait about 30 seconds for their body to adjust to the environment. The camera is taking the skin temperature, which the human body keeps in check very efficiently.
Two real-life examples of cold and hot temperatures:
In New York, the temperatures were averaging 45 degrees, and we had someone whose drive into work took about 20 minutes. While driving, they had the window rolled down and the air continually blowing into their face. They would walk from their car to the office and could feel their skin was cold. When walking into the office, they would get scanned, and their temperature would be between 96.9 and 97 Degrees. After waiting for about 60 seconds, they would rescan, and their temperature would average the mid 97 degrees.
In Arizona, where the temperature was over 100 degrees, we found that when someone was outside for a while, a cooling down about 20-30 seconds was necessary. Initially, their temperature registered at about 102, but after 20 seconds, it stabilized and showed their baseline temperature.
Something to keep in mind is that everyone is different. Two people who are excessively overheated may vary slightly in how fast their bodies regulated their temperature. One person might take about 10 seconds, while another person might take about 45 seconds. We are finding that the average is about 20-30 seconds for someone to regulate back to their baseline skin temperature.