How Cold Is Dry Ice in Fahrenheit?

Dry ice registers at about −109.3 °F (−78.5 °C) under normal atmospheric conditions, making it far colder than anything in your kitchen freezer. That number represents the sublimation point of solid carbon dioxide, the temperature at which it transitions directly from a solid into a gas without ever becoming a liquid. But the story is more interesting than a single number suggests, because dry ice can actually get colder than −109 °F depending on its surroundings, and understanding the practical realities of that extreme cold matters for anyone handling it.

Where the Number Comes From

Dry ice is simply carbon dioxide (CO₂) compressed and cooled into solid form. At standard atmospheric pressure, solid CO₂ sublimates at −78.5 °C, which converts to −109.3 °F. This has been a well-established figure in chemistry for nearly a century. Early calorimetric work measured the sublimation point at 194.67 K (the Kelvin equivalent of −78.5 °C) and confirmed the energy required for the solid-to-gas transition.¹ Industrial sources that produce dry ice pellets for cleaning and shipping work with this same baseline temperature.²

To put −109.3 °F in perspective, a standard home freezer runs at about 0 °F. Dry ice is roughly 109 degrees colder than that. Even the coldest naturally recorded air temperature on Earth, measured in Antarctica, only reached about −128.6 °F. Dry ice in your cooler is not far from that extreme, and it is sitting right in your hands (or should not be, as we will get to).

It Can Actually Get Colder Than −109 °F

The −109.3 °F figure assumes dry ice is surrounded by a CO₂-rich atmosphere at normal pressure. In real-world conditions, dry ice is almost always sitting in open air, which is overwhelmingly nitrogen and oxygen with only a trace of carbon dioxide. That matters more than you might expect.

Researchers investigating this effect found that when the air around a dry ice sphere contains 100% CO₂ at normal atmospheric pressure, the surface temperature holds steady at −78.5 °C (−109.3 °F), exactly as expected. But as the CO₂ concentration in the surrounding air drops, the dry ice gets colder. At 0% CO₂ in the surrounding gas, the measured surface temperature fell to roughly −97.3 °C, which is about −143 °F. That is nearly 19 °C (about 34 °F) colder than the textbook number.³

The mechanism behind this is called sublimative cooling, and it works similarly to how sweating cools your skin. When dry ice sublimates, the escaping CO₂ molecules carry energy away from the surface. In normal air with almost no CO₂, the sublimation happens more aggressively because the gas can disperse freely into the surrounding atmosphere. That faster sublimation pulls more heat from the solid, driving the temperature down well below −109 °F. The dry ice essentially reaches a “wet-bulb” temperature, a steady-state point where the rate of energy lost through sublimation balances the heat flowing in from the warmer surroundings.³

This means the block of dry ice you buy for a party or use to ship frozen goods is almost certainly colder than −109.3 °F at its surface, since it is sitting in air that contains less than 0.05% CO₂. The difference may not change how you use it, but it does mean the safety margins are a bit tighter than the textbook number suggests.

Why Dry Ice Skips the Liquid Phase

One of the features that makes dry ice useful is that it never melts into a puddle. At normal atmospheric pressure, solid carbon dioxide goes straight to gas. Liquid CO₂ does exist, but only under much higher pressure, roughly 5.1 times normal atmospheric pressure or above. Below that threshold, the solid-to-liquid transition simply is not available.

This is why dry ice is so popular for shipping perishable goods, including pharmaceuticals. It keeps things cold without producing any liquid runoff, and as it sublimates, the CO₂ gas is generally harmless in well-ventilated spaces. The pharmaceutical industry relies heavily on dry ice for cold chain transport, where temperature-sensitive biological drugs need to remain frozen during transit.⁴ One trade-off that is less commonly discussed is that the released CO₂ can dissolve into liquid solutions inside containers, lowering their pH. For most consumer uses this is irrelevant, but for drug formulations where pH matters, it is a real concern that pharmaceutical companies have to design around.

What Happens If You Touch It

At −109 °F or colder, dry ice will injure unprotected skin almost immediately. The injury is technically a cold burn, or frostbite, caused by rapid freezing of tissue. Contact for even a few seconds can cause reddening and pain similar to a mild burn, and longer contact can produce blisters or deeper tissue damage resembling a severe thermal burn. In extreme cases, prolonged exposure leads to gangrenous necrosis and can even require amputation of the affected area.⁵

The injuries fall on a spectrum:

Frostnip: The mildest form, causing numbness and white or waxy-looking skin. Usually heals on its own without lasting damage.
Superficial frostbite: Blistering occurs, similar to a second-degree burn. The skin reddens and swells after rewarming.
Deep frostbite: The tissue freezes through multiple layers, potentially damaging muscle and bone. This is the kind that can lead to permanent tissue loss.

Brief, accidental contact with dry ice is common and usually results in nothing worse than a sting and a small red mark. The real danger comes from prolonged contact, which can happen when someone grips a piece firmly or when dry ice gets trapped against skin inside a glove or pocket. Insulated gloves designed for cryogenic work are the standard protection. Kitchen oven mitts are better than bare hands but are not rated for these temperatures and should not be relied on for more than quick transfers.

The Suffocation Risk in Enclosed Spaces

The other major safety concern with dry ice has nothing to do with cold. As it sublimates, a single pound of dry ice produces roughly 250 liters of CO₂ gas. In a well-ventilated room, that gas dissipates harmlessly. In a confined or poorly ventilated space, CO₂ levels can rise quickly to dangerous concentrations, displacing oxygen and creating an asphyxiation hazard.⁶

CO₂ is heavier than air, so it tends to pool at floor level, in basements, walk-in freezers, and vehicle trunks. People have been seriously injured or killed after entering enclosed spaces where large quantities of dry ice were sublimating. The insidious part is that CO₂ at moderate concentrations causes confusion and drowsiness before a person realizes they are in danger, which can prevent them from leaving the area in time.

Practical guidelines for avoiding this are straightforward: never store large quantities of dry ice in a room or vehicle without ventilation, never place it in a sealed container (which can also build pressure and explode), and if you are transporting it in a car, crack a window. Laboratories and commercial facilities that handle dry ice in bulk are required to ensure that storage areas are properly ventilated and sized to prevent dangerous CO₂ accumulation.⁶

How Quickly It Disappears and How to Slow It Down

Dry ice does not last as long as most people expect. A five-pound block stored in a typical styrofoam cooler will sublimate completely in roughly 18 to 24 hours, depending on the ambient temperature and how often the cooler is opened. Smaller pellets vanish even faster because they have more surface area relative to their volume, giving heat more opportunity to reach the solid and drive sublimation.

If you need dry ice to last longer, insulation strategy matters. Researchers testing insulation packages found that lining the inner walls with a reflective layer such as aluminized mylar foil meaningfully reduced the sublimation rate compared to foam insulation alone.⁷ The reflective layer blocks radiant heat transfer, which is one of the main ways heat gets into a cooler. For practical purposes, this means wrapping your dry ice in layers of newspaper or towels inside the cooler, minimizing the air space around it, and keeping the cooler closed as much as possible. Some specialty shipping companies use vacuum-insulated panels for the same reason.

Buying block-form dry ice rather than pellets also helps. A single dense block has the least surface area for its mass and sublimates more slowly. If you need dry ice for an event or a long road trip, buy it as close to the time you need it as possible and in the largest single piece you can get.

The Hovering Effect on Flat Surfaces

If you have ever placed a chunk of dry ice on a smooth countertop or metal table, you may have noticed it glides around almost frictionlessly, as if floating on an invisible cushion. That is exactly what is happening. The extreme temperature difference between the dry ice and the room-temperature surface causes the bottom of the dry ice to sublimate rapidly, creating a thin layer of CO₂ gas between the solid and the surface. This gas layer acts as a lubricant, dramatically reducing friction.⁸

This is a version of the Leidenfrost effect, the same phenomenon that makes water droplets dance across a very hot pan instead of evaporating instantly. With dry ice the roles are reversed: the surface is the “hot” object and the dry ice is cold enough that gas production at the contact point is continuous and vigorous. The result is that a disk of dry ice on a smooth, flat surface behaves almost like an air hockey puck. Physicists have studied this as a low-friction system, and it turns out that the gas layer thickness and the friction coefficient depend on the mass of the dry ice disk and the smoothness of the substrate.

Common Uses That Depend on Extreme Cold

The reason dry ice is so widely used, despite the safety considerations, is that −109 °F fills a gap that regular ice cannot. Water ice tops out at 32 °F. Mechanical freezers can reach −20 °F or so in consumer models, and laboratory units can go much lower, but they require power and are not portable. Dry ice offers extreme cold without electricity, without liquid meltwater, and in a compact, lightweight form.

Some of the most common applications include:

Food shipping: Frozen goods shipped overnight or over long distances rely on dry ice to stay well below freezing throughout transit.
Medical and pharmaceutical transport: Vaccines, biological samples, and temperature-sensitive drugs are routinely packed with dry ice for cold chain logistics.⁴
Industrial cleaning: Dry ice blasting shoots pellets at high speed against surfaces to strip paint, remove residue, or clean industrial equipment. The pellets sublimate on impact, leaving no secondary waste to clean up.²
Fog effects: Dropping dry ice into warm water produces the dense, low-lying fog seen at concerts, theatrical productions, and Halloween displays. The “fog” is actually water vapor condensed by the cold CO₂ gas.
Emergency cooling: During power outages, dry ice placed in a freezer can keep food frozen for a day or two, far longer than water ice can manage.

Why You Cannot Make Liquid CO₂ by Warming Dry Ice

A common question people have after learning about dry ice is whether you can just warm it slightly and get liquid carbon dioxide. Under normal atmospheric pressure, the answer is no. Carbon dioxide has a triple point, the lowest pressure at which liquid can exist, at about 75 psi (roughly five times atmospheric pressure). Below that pressure, the only two options are solid and gas. This is why dry ice sublimates directly and why you will never see a puddle of liquid CO₂ forming under a block of dry ice at sea level.

Liquid CO₂ does exist inside high-pressure cylinders and certain industrial systems. CO₂ fire extinguishers, for example, store the substance as a liquid under pressure, and when the valve is opened, the rapid pressure drop causes some of it to flash into solid “snow” and some into gas. But under the conditions where anyone would encounter dry ice in daily life, the solid-to-gas pathway is the only one available.

Buying, Storing, and Disposing of Dry Ice

Dry ice is sold at many grocery stores, warehouse clubs, and specialty gas suppliers, typically in blocks or pellets. Prices vary but tend to be modest for the amount of cooling power you get. Because it sublimates continuously, you cannot stockpile it. Buy it as close to the time of use as possible.

For storage, a thick-walled styrofoam cooler is standard. Never store dry ice in a regular refrigerator or freezer, where the extreme cold can cause the thermostat to shut the unit off, and the CO₂ buildup inside the sealed compartment creates a pressure risk. Never place dry ice in an airtight container of any kind. The gas has to go somewhere, and a sealed container can become a pressure bomb.

Disposing of dry ice is simple: leave it in a well-ventilated area and let it sublimate. Do not put it down a sink, toilet, or garbage disposal, where the extreme cold can crack porcelain or pipes. Outdoors on a concrete surface is ideal. For smaller leftover amounts, leaving the cooler open with the lid off in a garage or well-ventilated room works fine. Just keep children and pets away from it until it is gone.

1
The Journal of Chemical Physics. Carbon Dioxide. The Heat Capacity and Vapor Pressure of the Solid. The Heat of Sublimation. Thermodynamic and Spectroscopic Values of the Entropy
2
Wear. Dry-ice blasting for cleaning: process, optimization and application
3
International Communications in Heat and Mass Transfer. Experimental and theoretical investigation of the dry ice sublimation temperature for varying far-field pressure and CO2 concentration
4
PubMed. The impact of dry ice exposure on pH change during biologics transport and mitigation strategies
5
Burns Open. Frostbite – manifestation and mitigation
6
PubMed Central. Lessons Learned: Asphyxiation Hazard Associated with Dry Ice
7
Applied Thermal Engineering. Experimental and numerical study of insulation packages containing dry ice pellets
8
PubMed. Dry ice hoverboard: Friction reduction by the Leidenfrost effect