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Calculate how cold the wind makes it feel, using the 2001 North American wind chill index. Applies at 10°C or below with wind of at least 4.8 km/h.
| Metric | Value |
|---|
The BoM uses the Steadman apparent temperature formula. Wind chill only applies when temperature is below 10°C and wind speed exceeds 4.8 km/h. Alpine areas (Snowy Mountains, Victorian Alps) experience severe wind chill.
WC = 13.12 + 0.6215T − 11.37V^0.16 + 0.3965T×V^0.16
Where T = air temperature (°C), V = wind speed (km/h)
Your body warms a thin layer of air held against your skin. That boundary layer is what keeps you comfortable in cold air. Wind strips it away and replaces it with fresh cold air, and your body has to heat it all over again — continuously.
Wind chill expresses that accelerated heat loss as a temperature: in still air, what temperature would cool exposed skin at the same rate as this combination of cold and wind?
The mechanism is simple enough to draw, and it explains every number on this page. Same 5°C air in both panels — only the wind differs:
Nothing about the air got colder. What changed is how fast your body loses heat to it — and that is the only thing wind chill measures. It is also why a windproof shell does more for you in these conditions than a thicker jumper: you are trying to keep the layer, not add insulation behind it.
This is the most common misconception about wind chill, and it has practical consequences.
Wind makes an object lose heat faster — your car cools down more quickly, a hot drink chills sooner, wet washing dries faster. But an object can only cool down to the air temperature, never below it. Heat flows from warmer to cooler, and once the object matches the air there is nothing left to drive further cooling.
| Situation | Air temp | Wind chill | What actually happens |
|---|---|---|---|
| Water pipe outdoors | +2°C | −6°C | Will not freeze. It cools faster, but only down to +2°C |
| Car radiator | −1°C | −12°C | Reaches −1°C sooner, not −12°C |
| Exposed skin | −1°C | −12°C | This is where wind chill matters — your body is generating heat, so faster loss means real cooling |
The difference is that living tissue produces heat continuously. Faster removal means your body cannot keep up, so skin temperature genuinely falls. An inert object has no heat source, so wind only changes how quickly it settles at the air temperature.
The formula in use today dates from 2001, when the US and Canadian weather services jointly replaced the older 1945 index following trials that measured heat loss from the faces of human volunteers in a chilled wind tunnel.
| Condition | Why |
|---|---|
| Air temperature 10°C or below | Above this, wind produces cooling comfort rather than cold stress |
| Wind speed 4.8 km/h or above | Below this the boundary layer is not meaningfully disturbed |
| V0.16 rather than V | The effect saturates — doubling wind speed does not double heat loss |
| Measured at 10 m | Standard weather-station height; wind at face level is typically lower |
If you compare this result against the "feels like" figure in the BoM app, they will usually disagree. That is expected — Australia does not use the wind chill index.
| Wind chill index | Apparent temperature (Australia) | |
|---|---|---|
| Used by | US National Weather Service, Environment Canada | Bureau of Meteorology |
| Adopted | 2001, replacing the 1945 index | Steadman 1994 |
| Inputs | Temperature, wind speed | Temperature, wind speed, humidity |
| Applies | Cold conditions only (≤10°C) | Across the temperature range |
| Includes direct sun | No | No |
The Bureau's approximation is AT = T + 0.33e − 0.70ws − 4.00, where e is water vapour pressure and ws is wind speed in metres per second. Because it carries a humidity term, damp cold and dry cold produce different figures — something the wind chill index cannot distinguish. For official Australian conditions, use the Bureau's forecast; use this page to understand the wind component on its own.
A winter morning in the Southern Highlands: 5°C with a 40 km/h wind.
| Step | Value |
|---|---|
| Air temperature | 5.0°C |
| Wind speed | 40 km/h |
| Wind chill | −0.7°C |
| Effective drop | 5.7°C below air temperature |
| Risk band | Low risk of frostbite; hypothermia possible with long exposure |
Five degrees sounds manageable. With that wind it loads exposed skin like freezing point — which is why standing on a sideline or waiting for a bus in an exposed spot feels so much worse than the forecast number suggests.
An alpine morning: −5°C with a 30 km/h wind.
| Step | Value |
|---|---|
| Air temperature | −5.0°C |
| Wind speed | 30 km/h |
| Wind chill | −13.0°C |
| Effective drop | 8.0°C below air temperature |
| Risk band | Low frostbite risk; real hypothermia risk without adequate clothing |
The drop grows as the air gets colder — 5.7°C in the first example, 8.0°C here. Wind and cold compound rather than simply adding.
Air temperature down the side, wind speed across the top, in km/h.
| Air temp | 10 | 20 | 30 | 40 | 50 | 60 |
|---|---|---|---|---|---|---|
| 10°C | 9 | 7 | 7 | 6 | 5 | 5 |
| 5°C | 3 | 1 | 0 | -1 | -1 | -2 |
| 0°C | -3 | -5 | -6 | -7 | -8 | -9 |
| -5°C | -9 | -12 | -13 | -14 | -15 | -16 |
| -10°C | -15 | -18 | -20 | -21 | -22 | -23 |
| -15°C | -21 | -24 | -26 | -27 | -29 | -30 |
| -20°C | -27 | -30 | -33 | -34 | -35 | -36 |
Shading follows Environment Canada's hazard bands. Values are only valid at 10°C or below with wind of at least 4.8 km/h.
These bands come from Environment Canada, which publishes the most widely used wind chill hazard classification.
| Wind chill | Risk | Exposed skin freezes in |
|---|---|---|
| 0 to −9°C | Low risk | Slight increase in discomfort |
| −10 to −27°C | Low frostbite risk | Hypothermia risk with long exposure and inadequate clothing |
| −28 to −39°C | Increasing risk | 10 to 30 minutes |
| −40 to −47°C | High risk | 5 to 10 minutes — faster in winds above 50 km/h |
| −48°C and below | Very high risk | 2 to 5 minutes |
Most of Australia never reaches the conditions this formula needs. It requires 10°C or below, which rules out large parts of the country for most of the year — and the extreme bands above, the ones Canadian charts are built around, are essentially academic here.
| Where it applies | Typical conditions |
|---|---|
| NSW and Victorian alpine areas | Sub-zero air with exposed ridgelines; the main Australian wind chill environment |
| Tasmania, especially highlands and west coast | Persistent cold with strong maritime wind |
| Inland winter mornings | Frosty starts across the tablelands, Riverina and inland WA |
| Southern coastlines in winter | Moderate temperatures but sustained strong wind |
| Pre-dawn starts anywhere | The coldest hour is usually just before sunrise |
Australia's lowest reliably recorded temperatures sit around −23°C in the Snowy Mountains. Even with strong wind that is a long way from the −40°C territory that dominates North American guidance — so for Australian planning, the useful part of the chart is the top half, not the bottom.
If you are moving, you make your own wind. A cyclist at 30 km/h in perfectly still air experiences the same 30 km/h airflow as someone standing in a 30 km/h wind — and a headwind adds to it directly.
| Air temp | 20 km/h | 30 km/h | 40 km/h | 60 km/h | 80 km/h | 100 km/h |
|---|---|---|---|---|---|---|
| 10°C | 7 | 7 | 6 | 5 | 4 | 4 |
| 5°C | 1 | 0 | -1 | -2 | -3 | -3 |
| 0°C | -5 | -6 | -7 | -9 | -10 | -11 |
| -5°C | -12 | -13 | -14 | -16 | -17 | -18 |
Effective wind chill at your own travel speed in still air. Add any headwind to the figure across the top.
Wind chill describes the air, not the person standing in it. At the same reading, individual risk varies widely — and knowing why a group is more exposed is more useful than knowing that it is.
| Group | Why risk is higher |
|---|---|
| Babies and young children | Greater surface area relative to body mass, so they lose heat faster, and they may not communicate discomfort |
| Older adults | Reduced ability to sense cold and generate heat, and a higher likelihood of conditions affecting circulation |
| People with poor circulation | Raynaud's, peripheral vascular disease and diabetes all reduce blood flow to the extremities, where frostbite starts |
| Outdoor workers | Sustained exposure with limited control over timing, often on exposed sites, and manual dexterity fails before any injury threshold |
| Hikers and campers | Remote from shelter, and heat production drops sharply the moment they stop moving |
| Cyclists and motorcyclists | Generate their own wind continuously, with no opportunity to warm up mid-ride |
| Anyone wet | Rain, immersion or sweat-soaked clothing dramatically accelerates heat loss |
| People sleeping rough | Prolonged exposure without shelter or the ability to warm up, often overnight when temperatures are lowest |
| People affected by alcohol | Alcohol widens surface blood vessels, which feels warming while accelerating heat loss — and it blunts the judgement needed to recognise the problem |
These are different conditions with different urgency. The information below is general and drawn from Environment Canada and Australian public health guidance; it does not replace medical assessment.
| Frostbite | Hypothermia | |
|---|---|---|
| What it is | Freezing of skin and underlying tissue | Core body temperature falling below normal |
| Affects | Extremities first — fingers, toes, ears, nose, cheeks | The whole body |
| Commonly reported signs | Numbness, loss of sensation, skin hard to the touch. Skin may look white or waxy on lighter skin tones; appearance may not change on darker tones | Shivering, slurred speech, confusion, clumsiness, drowsiness. In severe cases shivering stops |
| Response | Get medical help. Rewarm gradually — do not rub the area | Move indoors, remove wet clothing, insulate, seek medical help |
Australian cold-weather clothing advice differs from Canadian advice, because the conditions differ. Most Australian cold injury involves wind and rain at moderate temperatures rather than deep freeze — so staying dry and blocking wind matters more than raw insulation thickness.
| Wind chill | Suggested approach |
|---|---|
| +10 to 0°C | Windproof outer layer over a light insulating layer. Beanie and gloves if you will be stationary or on a bike |
| 0 to −10°C | Three layers: wicking base, insulating mid, windproof shell. Beanie, gloves and thick socks. Cover ears |
| −10 to −20°C | Thermal base layer, substantial insulation, fully windproof and water-resistant shell. Insulated waterproof boots, face covering |
| Below −20°C | Full winter protection with no exposed skin. Goggles or a face mask; minimise time outdoors and check on companions regularly |
Cold is a workplace hazard under Australian work health and safety law, and managing it is the employer's duty. Safe Work Australia publishes guidance on working in extreme temperatures, and state and territory regulators add their own.
What is wind chill?
Wind chill is a "feels like" temperature for cold conditions. It estimates the still-air temperature that would cool exposed skin at the same rate as the current combination of cold air and wind. Wind strips away the thin layer of warm air your body holds against your skin, so you lose heat faster than the thermometer alone suggests.
How is wind chill calculated?
Using the 2001 North American wind chill index: WCT = 13.12 + 0.6215T − 11.37V^0.16 + 0.3965T × V^0.16, where T is air temperature in °C and V is wind speed in km/h. It applies only at 10°C or below with wind of at least 4.8 km/h. The formula replaced a 1945 version after trials measuring heat loss from volunteers' faces in a chilled wind tunnel.
Does wind chill affect objects, cars or pipes?
Wind makes objects lose heat faster, but it cannot cool them below the actual air temperature. A pipe in +2°C air will not freeze no matter what the wind chill reads — it simply reaches +2°C sooner. Wind chill matters for people and animals because living bodies generate heat continuously, so faster removal means skin temperature genuinely falls.
What wind chill is dangerous?
Under Environment Canada's classification, frostbite risk increases rapidly below −27°C, with exposed skin freezing in 10 to 30 minutes between −28 and −39°C, in 5 to 10 minutes between −40 and −47°C, and in 2 to 5 minutes below −48°C. Above −27°C the main concern is hypothermia during long exposure rather than frostbite.
Can you get frostbite above 0°C?
Frostbite requires tissue to freeze, so skin must reach 0°C or below. Because wind chill describes a rate of heat loss rather than an actual temperature, a wind chill figure below zero when the air is above freezing does not mean skin will freeze. However, wet skin above freezing in strong wind can still cause non-freezing cold injury and contribute to hypothermia.
How does wind make it feel colder?
Your body warms a thin boundary layer of air against your skin, which acts as insulation. Wind continually removes that layer and replaces it with cold air, so your body must keep reheating fresh air. The faster this happens, the faster you lose heat — and the colder your skin feels, even though the air temperature has not changed.
Why does the Bureau of Meteorology show a different "feels like" temperature?
Because Australia does not use the wind chill index. The Bureau uses Steadman apparent temperature, which accounts for humidity as well as temperature and wind, and which applies across the whole temperature range rather than only in cold conditions. For official Australian forecasts, use the Bureau's figure.
How accurate is wind chill?
It is a standardised estimate, not a personal measurement. The 2001 index assumes an adult walking at about 5 km/h, facing into the wind, with a bare face and no direct sunlight. Clothing, body size, fitness, fatigue, wet skin and sun exposure all shift real heat loss significantly, so treat it as a planning figure rather than a precise reading.
Does wet skin change the wind chill risk?
Considerably. Evaporating moisture removes heat far faster than dry air convection alone. Occupational guidance suggests that for wet skin exposed to wind you should use an air temperature about 10°C lower than the actual reading. At 5°C in a 30 km/h wind, that shifts the effective figure from around 0°C to about −13°C.
Does wind chill apply to cyclists and motorcyclists?
Yes, and it applies more strongly than most riders expect, because movement generates wind even in still air. Travelling at 60 km/h on a 0°C morning gives a wind chill around −8.8°C on exposed skin, sustained for the whole ride. Any headwind adds directly to your own speed. Wind-blocking outer layers are more effective than thicker insulation alone.
Where in Australia does wind chill actually matter?
Mainly the NSW and Victorian alpine areas, Tasmania — particularly the highlands and west coast — inland winter mornings across the tablelands and Riverina, and exposed southern coastlines in winter. Australia's lowest recorded temperatures are around −23°C in the Snowy Mountains, so the extreme bands on North American charts have little practical relevance here.
What is the difference between frostbite and hypothermia?
Frostbite is localised freezing of skin and tissue, usually affecting fingers, toes, ears, nose and cheeks, with numbness and skin that feels hard. Hypothermia is a fall in core body temperature affecting the whole body, with shivering, confusion, slurred speech and clumsiness — and in severe cases shivering stops altogether. Both need medical attention; severe hypothermia is a medical emergency requiring 000.
The forecast maximum tells you very little about what an exposed ridgeline, an early start or a long descent will feel like. Wind is the variable that turns a manageable morning into a genuinely cold one, and it is the one most people leave out of their planning.
For official Australian conditions, use the Bureau of Meteorology's apparent temperature forecast. For the opposite end of the year, our heat index calculator covers heat and humidity, and the dew point calculator shows how much moisture the air is holding.