The heat generated by a burning cigarette is not a single, fixed number but fluctuates dramatically depending on the state of combustion. When tobacco ignites, it produces a concentrated point of heat subject to the airflow drawn through the cigarette. The temperature can vary by hundreds of degrees Fahrenheit between a smoker actively puffing and when the cigarette is left to smolder. These differences are a direct result of the amount of oxygen fueling the reaction and impact both the chemistry of the smoke and potential fire hazards.
Peak Combustion Temperature During Inhalation
The highest temperatures are achieved when a person actively inhales, or “puffs,” on the cigarette, forcing a rapid influx of oxygen into the burning material. This forced air movement intensifies the combustion process, causing the temperature at the center of the burning cone to spike rapidly. The peak temperature range during this active inhalation state typically reaches between 1,500°F and 1,700°F.
This brief, high-heat episode is highly localized within the burning zone, often referred to as the “cherry.” The sudden rush of air provides the necessary oxygen to fuel a near-complete combustion of the tobacco and other compounds. This extreme heat generates many of the chemical components found in the mainstream smoke drawn into the lungs. The temperature quickly begins to drop the moment the puff ends and the forced airflow ceases.
Resting Temperature of the Smoldering Cigarette
When a cigarette is placed in an ashtray and is not being actively smoked, it enters a lower-temperature state known as smoldering. The combustion continues, but the oxygen supply is limited to the slow, passive diffusion of air surrounding the cigarette. During this resting phase, the temperature of the lit tip remains consistently high, typically hovering around 1,100°F to 1,300°F.
This sustained heat is maintained because the burning tobacco creates its own insulating layer of ash. The ash acts as a barrier, trapping the heat and allowing slow pyrolysis and oxidation reactions to continue with minimal oxygen. This smoldering state is less efficient than the peak state, producing a different composition of sidestream smoke that drifts from the tip.
Fire Hazard Context
The sustained heat of the smoldering cigarette poses a substantial risk for unintended ignition of surrounding materials. Even at the lower resting temperature, the 1,100°F heat source is significantly hotter than the auto-ignition points of many common household items. For instance, paper begins to auto-ignite between 424°F and 500°F, while cotton fabric ignites around 513°F.
The danger stems not from the brief, extremely high peak temperature, but from the prolonged exposure to the lower, sustained smoldering heat. When a resting cigarette is dropped onto furniture or bedding, the continuous heat transfer can gradually raise the material’s temperature past its ignition point. Because the heat is contained and maintained by the ash, it provides the necessary time for materials to reach their kindling point and combust without an open flame. Unattended smoldering cigarettes are a leading cause of residential fire fatalities.