When a body stops beating, the loss of internal heat begins an inevitable decline in temperature, a phenomenon forensic investigators call algor mortis. Understanding this process is essential for accurately estimating the time of death and validating alibis.

The average adult human body temperature ranges from 98°F to 100°F, generated by metabolic processes such as digestion and muscle activity. At death, these processes cease and the heart stops pumping, causing the body’s heat to dissipate. Much like a pot of soup that cools to room temperature once removed from the stove, a corpse will ultimately equilibrate with its surrounding environment.

In a typical indoor setting with a steady ambient temperature, a body cools at a rate of approximately 1.5°F per hour. Within about 12 hours after death, the surface will feel cool to the touch, and by 24 hours the core temperature will have fallen to match the surrounding air. Once a body has been dead for more than a day, decomposition takes precedence and the reliability of algor mortis for time‑of‑death estimation diminishes.

Factors that Influence Algor Mortis

Several variables can accelerate or delay cooling:

• Ambient temperature and humidity – A corpse in a hot, humid rainforest will cool more slowly than one in a cold, dry tundra.
• Body composition – Individuals with higher body mass index or substantial subcutaneous fat retain heat longer due to the insulating properties of fat.
• Clothing and coverings – Heavy, insulated garments can trap heat, extending the cooling period.
• Age – Very young or elderly individuals tend to cool more rapidly because of thinner skin and reduced metabolic reserves.

Forensic investigators must account for these factors when reconstructing the scene and determining the likely time of death.