Which Is Colder: Minus 40°C or Minus 40°F?
It’s a common conversation among those exposed to both measurement systems to hear them try to answer the question, “which is colder, -40° C or -40° F?” It looks like a trick question, since in classic guessing fashion, you try to solve the riddle by thinking that one of the two has to be colder, but here’s the twist: -40° C and -40° F are both the same temperature. They are the only temperature that is at a point of intersection for both scales.
Though it does feel especially simple, it’s often a surprise to many students, travelers, weather enthusiasts, or anyone who is exposed to a measurement system that employs a different temperature measurement scale, as is the case for most of the population, that there is such a phenomenon.
In this document, you are going to learn the opposite of the impossibility that is -40° C is -40° F, the mechanics of the two measurement systems employed to measure temperature, the various extreme temperature ranges, and the effects such temperatures have on human physiology and the protective measures that will keep you safe in prolonged exposure to the extreme temperatures we refer to as dangerously cold weather.
What Is the Basis for Saying -40° C and -40° F Are Equal?
For the most part, temperature values are different on the Celsius scale when compared to values on the Fahrenheit scale.
To illustrate this, consider the following:
| Celsius | Fahrenheit |
|---|---|
| 0°C | 32°F |
| 10°C | 50°F |
| 20°C | 68°F |
| 30°C | 86°F |
The inconsistency with the values becomes noticeable as temperatures drop below the freezing point of 0°C / 32°F, and it is only then that the two temperature scales finally agree.
-40°C = -40°F
This is the only temperature that provides the two measurement systems with a satisfying numerical value.
Because of this rare occurrence, weather updates from countries that use Celsius will be the same as those from countries that use Fahrenheit, as they will both drop to -40 without a need for conversion.
Understanding Celsius and Fahrenheit
Before analyzing why temperatures are equal, we must understand how the Celsius and Fahrenheit temperature scales are cataloged and created.
Celsius Scale
The Celsius scale is primarily used by the majority of countries around the globe.
As designed around water:
- 0°C is when water freezes
- 100°C is when water boils
Because Celsius utilizes 100 divisions in between water’s freezing and boiling point, it is preferred by scientists in calculations and lab work.
Countries such as Canada, Australia, the UK, and almost all of Europe mostly use Celsius in their day-to-day weather reports.
Fahrenheit Scale
The Fahrenheit scale is primarily used by the US and some other areas around the world.
On the scale:
- Water’s freezing point is 32°F
- Water’s boiling point is 212°F
Instead of 100 in Celsius, Fahrenheit divides freezing and boiling by 180.
This gives temperatures in Fahrenheit the appearance of being more precise, but for scientific calculations and measurements, both are accurate.
The Formula That Explains Everything
Celsius to Fahrenheit uses the formula:
°F = (°C × 9/5) + 32
Using -40°C, let’s see what -40°F is.
Step 1
-40 × 9 = -360
Step 2
-360 ÷ 5 = -72
Step 3
-72 + 32 = -40°F
This proves mathematically that:
-40°C = -40°F
Using Celsius conversion in Fahrenheit also gets us -40°C.
Why This Temperature Is So Unique
This is famously known as the perfect mathematical intersection of the two temperature scales, and for good reason. Most other temperatures do not match.
Only one row in the temperature chart shows the same values in the Celsius and Fahrenheit systems:
| Celsius | Fahrenheit |
|---|---|
| 0°C | 32°F |
| -10°C | 14°F |
| -20°C | -4°F |
| -30°C | -22°F |
| -40°C | -40°F |
| -50°C | -58°F |
What makes this fact special if not fascinating? What makes -40°F/-40°C a good school example, or a good example for a course on weather or a course on engineering?
What Does -40° Actually Mean?
Seeing -40 in a weather forecast likely does not say much about the severity of the situation. Most people may not be aware of just how dangerous that temperature is. Other than its famous freezing skin, -40° exhibits the following properties:
- It is serious frostbite weather.
- In -40 weather, breathing becomes painful.
- Most vehicles, and their batteries, freeze.
- Water freezes instantly.
- Ice is freezing and brittle.
- Snow becomes powdery.
People often say that -40° feels like breathing in a million needles. It is also not safe to walk outside for any extended period of time without the proper clothing.
Where in the World Reaches -40°F/-40°C?
Many people living in places with mild to warm climates may never experience temperatures this low.
However, several places in the world do experience them regularly. These include:
- Northern Alaska
- Northern Canada
- Siberia
Northern Alaska, Northern Canada, and Siberia each experience especially long, harsh winters. Many of these areas’ remote communities even insulate their homes and store fuel several months in advance to prepare for the cold. They also winterize their vehicles.
Millions of residents and workers manage to adapt to the environment.
Interior Antarctica
Antarctica is the most frigid of the 7 continents.
The winter temperatures can easily drop beyond -40°C, and even less than -60°C are commonplace.
Some research stations in Antarctica can get winter temperatures below -80°C.
Greenland
Some parts of Greenland can get winter temperatures close to -40°C.
Along with the freezing temperatures, especially strong winds can make thermal winds feel even colder.
Wind Chill Makes It Seem Colder
A big winter weather myths is that only air temperatures matter.
But it doesn’t. It can feel even colder.
Wind chill is how air temperatures, along with strong winds, can make your body feel even colder.
For example:
- Air Temperature = -40°C
- Moving Wind = 25 mph
It can lead your body to feel -55°C.
This can make frostbite even more probable.
Winds chill can even make winter weather prone dangerous, so meteorologists often issue wind chill warnings to enhance awareness.
What Happens to the Body at -40°C (-40°F)?
Extreme cold can change your body quicker than you think.
At -40° the body can even drop to a below normal core temperature of 37°C (98.6°F) bringing on hypothermia.
Without proper winter clothing, even a brief exposure can lead to frostbite.
What Are the Early Signs of Cold Exposure?
It only takes a few minutes to experience:
- Shivering
- Fingers and toes going numb
- Skin going red or pale
- Difficulty moving hands
- Slower reaction time
- Mild confusion
These symptoms are your body’s way of slowing blood flow to your hands and feet to preserve heat.
What Are the Serious Effects of Cold Exposure?
The longer cold exposure lasts, the more serious the effects become:
- Frostbite
- Hypothermia
- Loss of coordination
- Slurred speech
- Confusion
- Unconsciousness
- Organ failure in extreme cases
This is why cold warnings are issued when it is close to reaching -40°.
What Is Frostbite?
Frostbite is when the skin and tissue beneath it freeze.
At -40° Celsius or Fahrenheit, skin can start freezing within the first 5–10 minutes of it being exposed, especially in the presence of strong winds.
What Areas Are Most Likely to Frostbite?
- Fingers
- Toes
- Nose
- Ears
- Cheeks
- Chin
What Are the Symptoms of Frostbite?
- A tingling or numb sensation
- Skin going white or grayish
- Skin becoming hard or waxy
- Skin forming blisters after warming
Worse frostbite can permanently numb and damage the skin and tissues, and may require surgery or amputation.
What Is Hypothermia?
Hypothermia is when the body’s core temperature drops below 95°F (35°C).
Hypothermia impacts the overall body, unlike frostbite.
What Are the Warning Signs of Hypothermia?
- Shivering (but this will stop with a drop in core temp)
- Fatigue
- Slowed breathing
- Confusion
- Drowsy
- Poor decisions
- Weak pulse
Hypothermia requires immediate treatment or it can become fatal.
Can Humans Survive at -40°?
Yes! It all depends on the preparation.
There are places inhabitable in winter with average temperatures at -40°C or -40°F, and the people there stay safe by properly planning using insulated clothing and heated shelters.
What Is Essential Winter Clothing?
Base Layer
- Moisture-wicking thermal underwear
- Wool or synthetic fabrics
Middle Layer
- Fleece or insulated jacket
- Wool sweaters
Outer Layer
- Waterproof winter coat
- Windproof shell
Accessories
- Thick gloves or mittens
- Insulated boots
- Wool socks
- Face mask
- Scarf
- Thermal hat
Layering traps warm air and protects your body from wind and moisture.
How Vehicles Perform at -40°
Cars experience many problems during extreme cold.
Common Issues
- Dead batteries
- Thick engine oil
- Frozen fuel lines
- Low tire pressure
- Frozen windshield washer fluid
- Stiff rubber seals
Many northern communities plug in engine block heaters overnight to keep engines warm enough to start in the morning.
Everyday Objects Behave Differently
Extreme cold affects more than people.
Electronics
Phones may lose battery power rapidly because lithium-ion batteries perform poorly in freezing temperatures.
Plastics
Some plastics become brittle and may crack more easily.
Metal
Metal feels much colder because it transfers heat away from your skin quickly.
Rubber
Rubber tires become stiffer, reducing traction on icy roads.
Wildlife That Thrives in Extreme Cold
Many animals have evolved incredible adaptations that allow them to survive temperatures near or below -40°C.
Polar Bears
- Thick insulating fur
- Large fat reserves
- Black skin that absorbs heat
Arctic Foxes
- Dense winter coats
- Fur-covered paws
- Small ears that reduce heat loss
Snowy Owls
- Heavy feather insulation
- Excellent hunting abilities during winter
Musk Oxen
Their long outer hair protects an incredibly warm undercoat called qiviut, one of the warmest natural fibers in the world.
Here We Have Some Interesting Facts at -40°
- It’s the only temperature where -40°C and -40°F are the same.
- Your breath can freeze. Moisture in your breath can freeze into tiny ice crystals.
- Your eyelashes can freeze together. Water vapor from blinking can freeze on eyelashes.
- Hot water can turn into snow. Careful, hot water thrown into very cold air can create a cloud of tiny ice crystals.
- Batteries drain quickly at -40°. All electronic devices, including phones, can easily lose power.
Myths About Minus 40°
1. -40°F Is Colder Than -40°C?
False. They are the same temperature.
2. -40° Cars Won’t Start?
Not True. Cars with proper winter maintenance and a healthy battery often start successfully.
3. Does It Always Snow at -40°?
Not necessarily.
4. Are -40° Temperatures Only Experienced in the Polar Regions?
False.
5. Where Can -40° Be Experienced?
Alaska, Siberia, northern Canada and Mongolia are some mountainous regions can all experience -40°.
Celsius and Fahrenheit Comparison Chart
| Celsius | Fahrenheit | Description |
|---|---|---|
| 40 | 104 | Hot summer day |
| 30 | 86 | Warm |
| 20 | 68 | Room temp |
| 10 | 50 | Cool day |
| 0 | 32 | Freezing |
| -10 | 14 | Cold day |
| -20 | -4 | Very cold |
| -30 | -22 | Dangerous cold |
| -40 | -40 | Same temp |
| -50 | -58 | Extreme arctic |
Why This Question Is So Popular
Possible reasons for the search “which is colder -40C or -40F”:
- Could be comparing weather reports of different countries.
- Students encounter this in both science and math classes.
- International travelers can encounter both while planning their trips.
- It’s an interesting scientific fact and people generally like to learn something new.
For this question the answer is simple but memorable.
They are both the same temperature.
Final Answer
So Which Is Colder: -40°C or -40°F?
Neither. -40°C and -40°F are both the same temperature.
This is a one-of-a-kind mathematical phenomenon that occurs between the Celsius and Fahrenheit temperature systems. It is the only point in the system where both scales can show the same exact numeric value.
Although the systems show the same number, -40°C and -40°F represent the same temperature, which is, of course, very dangerous to be in. It requires serious planning and preparation to be out in the cold of -40°.
Knowing this is an interesting fact and useful for international planning and scientific learning.
Common Questions Answered
Is -40°C Colder Than -40°F?
No, both of these are the same temperature.
What Causes the Intersection of Celsius and Fahrenheit at -40?
Due to the conversion equations. These two systems of temperature measurement can only equate at one point, -40°.
Which Regions Follow the Celsius Scale?
Just about all regions, with the exception of the United States and a couple of Caribbean countries, utilize Celsius. The latest to join the majority was Yemen in 2012.
Which Region Uses Fahrenheit?
Primarily the US, with the exception of a few Caribbean nations, utilizes Fahrenheit.
Is It Possible to Live in -40°?
Yes, with adequate insulation, proper shelter, winter clothing, and other preparations, it is possible to live in these conditions. However, like any extreme weather conditions, there is a high risk of frostbite and hypothermia if exposed continuously without precautions.
How Quickly Can Frostbite Occur in -40° Weather?
If there is adequate shelter from the wind, frostbite can begin in 10–30 minutes. If wind is a factor, frostbite can occur in less than 10 minutes. The greater the surface area of skin exposed, the less time it will take for frostbite to occur.
How Quickly Does Water Freeze in -40°?
It can take seconds, minutes or longer to freeze water at -40° depending the environment the water is in, the conditions the water is in, and the state the water is in. If the water is in motion, it will take longer for it to freeze compared to if the water is still.
Why Does the Temperature Continue to Drop When It Reaches -40° With Wind?
The air temperature remains the same, but the wind begins to take heat away from your body more quickly, making it feel much colder. This is known as the wind chill effect.
