The Wind Chill Temperature Index
information from the US National Weather Service
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What is Wind Chill Temperature?

It is the temperature it "feels like" outside and is based on the rate of heat loss from exposed skin caused by the effects of wind and cold.
As the wind increases, the body is cooled at a faster rate causing the skin temperature to drop. Wind Chill does not impact inanimate objects like car radiators and exposed water pipes, because these objects cannot cool below the actual air
temperature.
What does this mean to me?

The NWS will inform you when Wind Chill conditions reach critical
thresholds. A Wind Chill Warning is issued when wind chill temperatures
are life threatening. A Wind Chill Advisory is issued when wind chill
temperatures are potentially hazardous.



What is Frostbite?

Frostbite is an injury to the body caused by freezing body tissue. The most
susceptible parts of the body are the extremities such as fingers, toes, ear
lobes, or the tip of the nose Symptoms include a loss of feeling in the
extremity and a white or pale appearance. Medical attention is needed
immediately for frostbite. The area should be SLOWLY re-warmed.



What is Hypothermia?

Hypothermia is abnormally low body temperature (below 95 degrees
Fahrenheit). Warning signs include uncontrollable shivering, memory loss,
disorientation, incoherence, slurred speech, drowsiness, and apparent
exhaustion. Medical attention is needed immediately. If it is not available,
begin warming the body SLOWLY.



Tips on how to dress during cold weather.

>Wear layers of loose-fitting, lightweight, warm clothing. Trapped air
between the layers will insulate you. Outer garments should be tightly
woven, water repellent, and hooded.

>Wear a hat, because 40% of your body heat can be lost from your head.

>Cover your mouth to protect your lungs from extreme cold.

> Mittens, snug at the wrist, are better than gloves.

>Try to stay dry and out of the wind.
For more Information on cold-related health problems and outdoor safety
visit the web site from the Centers for Disease Control and Prevention (CDC) at:
http://www.cdc.gov/nceh/hsb/extremecold
Visit the National Weather Service Wind Chill web page at:
http://www.nws.noaa.gov/om/windchill/
Visit Environment Canada's Wind Chill web page at:
http://www.msc.ec.gc.ca/windchill/index_e.cfm
Wind Chill - Frequently Asked Questions

1. What is wind chill temperature?

A. The wind chill temperature is how cold people and animals feel when outside. Windchill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. Therefore, the wind makes it FEEL much colder. If the temperature is 0 degrees Fahrenheit and the wind is blowing at 15 mph, the wind chill is -19 degrees Fahrenheit. At this wind chill temperature, exposed skin can freeze in 30 minutes.

2. Can wind chill impact my car's radiator or exposed water pipe?

A. The only effect wind chill has on inanimate objects, such as car radiators and water pipes, is to shorten the amount of time for the object to cool. The inanimate object will not cool below the actual air temperature. For example, if the temperature outside is -5 degrees Fahrenheit and the wind chill temperature is -31 degrees Fahrenheit, then your car's radiator will not drop lower than -5 degrees Fahrenheit.

3. What is FROSTBITE?

A. You have frostbite when your body tissue freezes. The most susceptible parts of the body are fingers, toes, ear lobes, or the tip of the nose. Symptoms include a loss of feeling in the extremity and a white or pale appearance. Get Medical attention immediately for frostbite. The area should be SLOWLY re-warmed.

4. What is HYPOTHERMIA?

A. Hypothermia occurs when body temperature falls below 95 degrees Fahrenheit. Determine this by taking your temperature. Warning signs include uncontrollable shivering, memory loss, disorientation, incoherence, slurred speech, drowsiness, and exhaustion. Get medical attention immediately. If you can't get help quickly, begin warming the body SLOWLY. Warm the body core first, NOT the extremities. Warming extremities first drives the cold blood to the heart and can cause the body temperature to drop further--which may lead to heart failure. Get the person into dry clothing and wrap in a warm blanket covering the head and neck. Do not give the person alcohol, drugs, coffee, or any HOT beverage or food. WARM broth and food is better. About 20% of cold related deaths occur in the home. Young children under the age of two and the elderly, those more than 60 years of age, are most susceptible to hypothermia. Hypothermia can set in over a period of time. Keep the thermostat above 69 degrees Fahrenheit, wear warm clothing, eat food for warmth, and drink plenty of water (or fluids other than alcohol) to keep hydrated. NOTE: Alcohol will lower your body temperature.

5. Tips on How to Dress during cold weather

A.
The best way to avoid hypothermia and frostbite is to stay warm and dry indoors. When you must go outside, dress appropriately. Wear several layers of loose-fitting, lightweight, warm clothing. Trapped air between the layers will insulate you. Remove layers to avoid sweating and subsequent chill. Outer garments should be tightly woven, water repellent, and hooded. Wear a hat, because half of your body heat can be lost from your head. Cover your mouth to protect your lungs from extreme cold. Mittens, snug at the wrist, are better than gloves. Try to stay dry and out of the wind.

6. Avoid Overexertion

A. Your heart is already working overtime in cold weather. The strain from the cold and the hard labor of shoveling heavy snow, walking through drifts or pushing a car may cause a heart attack. Sweating from overexertion could lead to a chill and hypothermia.

7. Is there a Celsius version of the chart?

A.
We will look into adding a Celsius version to the web page calculator. In the mean time, you can go to http://www.wrh.noaa.gov/slc/projects/wxcalc/windChill.php

8. Windchill factor vs. wind chill temperature.

A.
These terms are almost the same. The wind chill factor describes what happens to a body when it is cold and windy outside. As wind increases, heat is carried away from the body at a faster rate, driving down both skin temperature (which can cause frostbite) and eventually the internal body temperature (which can kill).

Windchill temperature is a unit of measurement to describe the wind chill factor. Windchill temperature is a measure of the combined cooling effect of wind and temperature. Since you and your husband ride motorcycles, you can insert your driving speed to estimate the wind speed and the outside temperature. These two parameters combined will give you the wind chill temperature, or how it feels to you skin. On the bottom of the wind chill chart is the updated wind chill temperature formula.

9. Is it possible to get frostbite if the temperature is above freezing but the wind chill is below freezing?

A.
The air temperature has to be BELOW freezing in order for frostbite to develop on exposed skin. Wind chill can bring the temperature to below freezing for humans and animals.

10. How is the Windchill is calculated?

A.
The wind chill temperature is calculated using the following formula:

Windchill (ºF) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)

Where: T = Air Temperature (F)
V = Wind Speed (mph)
^ = raised to a power (exponential)


Windchill Temperature is only defined for temperatures at or below 50 degrees F and wind speeds above 3 mph. Bright sunshine may increase the wind chill temperature by 10 to 18 degrees F.

11. When does the National Weather Service issue a Windchill Advisory or Warning?

A.
Criteria for issuing Windchill Warnings and Advisories are set locally. For the Rochester, NY area, Windchill Warnings are issued when the Windchill Temperature is expected to fall at or below -25 F. Windchill Advisories are issued when the wind chill temperature is expected to fall between -15F and -24F.

12. Does wind chill only apply to people and animals?

A. Yes.
The only effect wind chill has on inanimate objects, such as car radiators and water pipes, is to more quickly cool the object to cool to the current air temperature. Object will NOT cool below the actual air temperature. For example, if the temperature outside is -5 degrees Fahrenheit and the wind chill temperature is -31 degrees Fahrenheit, then your car's radiator will not drop lower than -5 degrees F.

13. Does humidity or being near a large water body affect on wind chill?

A.
When we tested the new Windchill Temperature Index (WCTI), our researchers applied the new index to 12 test subjects. The results of the tests showed that relative humidity was an insignificant weather parameter, less than one degree at worst. To simplify the calculation, relative humidity was left out of the formula.

We did research a wet wind chill or blowing water spray. This research was to simulate a person near a body of water or a mariner. These findings are being finalized and may be incorporated for the winter season 2003-2004.

14. How does this chart apply to children?

A
. The tests that were done on Windchill were conducted on adult subjects. For legal and safety reasons, NWS could not ask for child volunteers. Use the existing chart as a starting point and be even more cautious with children, seniors and persons with compromised health.



Information on cold-related health problems and winter storm safety from the Centers for Disease Control and Prevention (CDC)
NOAA <http://www.noaa.gov/>,
National Weather Service http://www.weather.gov
Office of Climate, Water, and Weather Services http://www.weather.gov/os/
1325 East West Highway
Silver Spring, MD 20910