Join the Car Talk Community!

Discussion Rules

Welcome to the Car Talk Community!

Want to ask a question or join the discussion? Great! Join now.

Sign In Register

Wind chill on a car

Tom and Ray,
I have to argue with your comments that wind chill does not affect a car. Wind chill affects anything with an internal heat source; the wind blows away the heat. If it is cold and the wind is blowing, it will take longer for a car to warm up much like Tom said it will cool off faster if windy.

Also, Tom is right that the car will not get colder than the real temperature. Neither would a human.

Kriss
«13

Comments

  • True, windchill affects anything with an internal heat source. So, if the car is standing still in cold weather, it would lose more heat in a wind than if there was no wind.

    However, when you are driving there is no difference, since your speed is nearly always faster than the wind.

    The term winchill used by weather stations more refers to the evaporation from your skin caused by the warm envelope being constantly blown away by the wind. I have walked outside at 0 degrees on a windstill sunny day with low humidity and felt OK.
  • What Tom and Ray meant by wind chill not effecting a car....is what MOST people get confused about. Wind chill is rate of cool...NOT how cold something will get.

    If the temp is 40 degrees outside...but a windchill of 30....water will NOT freeze. Many people see the 30 degrees and automatically think that's how cold it will get.
  • @MikeInNH Assuming the car and engine are warm, a windy day would remove more heat envelope from the car and presumably make the heater work harder, or take a little longer to heat up the car.

    Tom and Ray are right that cars don't feel the chill due to wind, and their temperature will stay the same. I know some folks who look at the weather channel and when it shows 25F or so chill factor while the actual temperatue is above freezing they want to put their cars inside or plug in the block heater.
  • "plug in the block heater"
    Thats funny. Without the block heater, the car is unaffected by the wind chill, but the block heater provides the car with an internal heat source, so then the car is affected by the wind chill.
  • edited March 2013
    @keith That's how some folks "reason"! Personally, I don't plug the car in until the forecast temperature is in the low 20s. The car starts in any temperature, but it warms up muchquicker with the heater plugged in.
  • edited March 2013
    Wind chill is a calculation of from NOAA

    "Wind chill temperature is a measure of the combined cooling effect of wind and temperature. As wind increases, heat is carried away from the body at a faster rate, driving down both the skin temperature (which can cause frostbite) and eventually the internal body temperature (which can kill). The Wind Chill Temperature index is the measure of this relationship.

    Your engine has no concept of wind chill because there is no inherent temperature loss making it feel colder than it really is. It is a factor of increased cooling effect to get to a temperature, rather than the actual temperature. Your body temp is 98.6 average, wind makes you cool faster to the temp point, the engine is not under a 98.6 requirement. Sure an engine may cool faster with big winds but it will not feel below ambient temp as you may.
  • @MikeInNH Assuming the car and engine are warm, a windy day would remove more heat envelope from the car and presumably make the heater work harder, or take a little longer to heat up the car. - See more at: http://community.cartalk.com/discussion/2290684/wind-chill-on-a-car#latest
    Agreed....And nothing I said disagrees with that statement.
  • 40 MPH North Wind.

    Car parked facing North. The air speed of the wind blowing at the front of the car is 40 mph.

    Car drives North into wind at 40 mph. The air speed of the wind blowing at the front of the car is 80 mph.

    Car drives South with the wind at 40 mph. The air speed of the wind blowing at the front of the car is 0 mph.

    Think in terms of radiator.

    CSA
  • I would argue that it isn't a calculation, but rather a mathematical description of how quickly heat is dissipated from an object.

    I would also argue that an "internal heat source" is a varable in the equation used to calculate the chill factor that the news warns us about, but in an automobile with the engine not running the value of that variable is simply zero. In short, a specfic mass generating X btus of heat per hour will dissipate heat in a Y mph wind at a rate of Z. With X being a lower value, Z will be higher. Etc.

    Humans generate heat at a known rate. Therefore, the ambient temperature and rate of wind can be readily factored in to determine how quickly heat will be dissipated and thus, what eth equivalent ambient temperature dissipation rate would be without wind.....which gives you the chill factor.

    But in truth I think we're all arguing semantics. Simply, wind has an effect on how quickly an engine reaches ambient temperature. But only if it's passing over the engine. That's why we always tried to park heading away from the wind in North Dakota. It helps.
  • edited March 2013
    @the_same_mountainbike I cannot find a definition of mathematical description, so I cannot respond to "I would argue that it isn't a calculation, but rather a mathematical description"

    I can find this "The NWS Windchill Temperature (WCT) index uses advances in science, technology, and computer modeling to provide an accurate, understandable, and useful formula for calculating the dangers from winter winds and freezing temperatures."
    http://www.nws.noaa.gov/om/windchill/
    Just like to make sure I state things correctly, so enlighten me, no offense intended.
This discussion has been closed.