How Long Does It Take For A Body To Get Cold After Death?

If you're a fan of crime shows, you know that one of the first questions posed in any homicide case is what the time of death was. This is crucial for piecing together the victim's last moments, and determining whether a suspect's alibi holds up. One of the main things used to estimate time of death is the phenomenon of algor mortis. You've likely heard of rigor mortis, the process by which the body stiffens after death, but algor mortis (literally "coldness of death") focuses on a different trait: body temperature.

The average human body temperature is between 98 and 100 degrees Fahrenheit. This heat is generated within the body by internal processes like digestion and muscle movements. Death halts these processes, and thus stops the body from producing its own heat. It also stops the heart from pumping and circulating heat through the body. Just as a pot of soup eventually cools to room temperature once it's removed from the heat, a body freshly removed from life will ultimately cool to the same temperature as its surroundings.

After death, the body cools by roughly 1.5 degrees Fahrenheit per hour. It will typically be cool to the touch by around 12 hours after death, and the internal heat will have fully dissipated by 24 hours after death. Once a body has been dead for more than a full day, it starts to go into the more extreme stages of the human decomposition process and algor mortis loses its value in establishing time of death.

It's a bit inaccurate to say that a body goes cold after death. Although it internally cools from its standard heat, it only drops to room temperature (or outdoor temperature, depending on the scene of death). Just as the surrounding environment dictates the temperature, it also affects the rate of cooling, and there are several environmental factors that can either speed up or slow down algor mortis. The most obvious of these is the surrounding temperature, as a corpse in a hot and humid rainforest will cool much slower than a corpse in the Arctic tundra. Temperature and humidity are two of the biggest factors in determining how fast a body decomposes altogether, and algor mortis is an early tell of how long that entire process will take.

The body type of the deceased person also has a big impact on the rate of algor mortis. Generally speaking, the higher a person's body mass index, the slower their body will cool, especially if they have significant amounts of subcutaneous fat, which has an insulating effect. On the subject of insulation, what the person was wearing at their time of death can also affect algor mortis, potentially trapping heat and slowing the process. People who die in either old age or infancy also tend to cool faster than people in the middle stages of life. All of these factors must be accounted for anytime investigators search for the time of death.