Calculating windchill...
#1
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Calculating windchill...
If the temperature is 21°F and I'm cycling at 12mph into a 24mph headwind, is the windchill calculated using 36mph?
Similarly, if I'm traveling at 24mph with a 24mph tailwind is windchill negated?
Similarly, if I'm traveling at 24mph with a 24mph tailwind is windchill negated?
#2
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my guesses
yes, 21 - 36 = -15 degrees
yes
winter is coming back to my area Brrrr!
yes, 21 - 36 = -15 degrees
yes
winter is coming back to my area Brrrr!
#3
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#4
Old Dog, New Tricks
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Windchill and cycling ...
(Initially, I posted this query in the winter cycling sub-forum. But this sub-forum seems to get a lot more traffic)
If the temperature is 21°Farenheit and I'm cycling at 12mph into a 24mph headwind, is the windchill calculated using 36mph?
Similarly, if I'm traveling at 24mph with a 24mph tailwind is windchill negated?
If the temperature is 21°Farenheit and I'm cycling at 12mph into a 24mph headwind, is the windchill calculated using 36mph?
Similarly, if I'm traveling at 24mph with a 24mph tailwind is windchill negated?
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Looks as if you have an answer in "Winter Cycling."
#6
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#7
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This is what google says. I Have no idea if it’s accurate.
“Calculate the wind chill using the National Weather Service's new formula. Multiply the temperature by 0.6215 and then add 35.74. Subtract 35.75 multiplied by the windspeed calculated to the 0.16 power. Finally, add 0.4275 multiplied by temperature, multiplied by wind speed calculated to the 0.16 power.”
“Calculate the wind chill using the National Weather Service's new formula. Multiply the temperature by 0.6215 and then add 35.74. Subtract 35.75 multiplied by the windspeed calculated to the 0.16 power. Finally, add 0.4275 multiplied by temperature, multiplied by wind speed calculated to the 0.16 power.”
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Yes, use your airspeed.
When I still had a motorcycle I used a wind chill chart like this one. Note it has the same formula mentioned above
https://www.weather.gov/safety/cold-wind-chill-chart
When I still had a motorcycle I used a wind chill chart like this one. Note it has the same formula mentioned above
https://www.weather.gov/safety/cold-wind-chill-chart
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#9
Non omnino gravis
As windchill is a relative expression of an absolute (that is, temperature) being outside @ 21ºF riding into a 24mph wind, the temperature is 21ºF. Any exposed skin will experience the sensation of temperature around 5ºF. This is above the threshold for frostbite. Riding 12mph into a 24mph headwind is absolutely not 12 + 24. You're not somehow going faster into the wind than the wind is hitting you. Windchill would be based on the wind speed, and should be essentially moot, as I don't know why anyone would be going out with bare arms and shorts in 21ºF temps to begin with.
Meanwhile, I'm sitting here thankful I can never experience such conditions here. I don't think I've ever seen it windy with the temps below 40ºF or so. Most of our wind comes from the desert, so if it's windy, it's warming.
Meanwhile, I'm sitting here thankful I can never experience such conditions here. I don't think I've ever seen it windy with the temps below 40ºF or so. Most of our wind comes from the desert, so if it's windy, it's warming.
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#10
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My understanding is that this is the formula for determining windchill for stationary objects.
What I'm unsure of is if bike velocity and windspeed can be combined by simple addition to determine windchill "in motion", or if there is an exponential factor to consider as when two cars collide head on.
When two cars collide head on, each traveling at 15mph, the force of their collision is not the sum total of their combined velocities. Is it not the same when riding into a headwind?
What I'm unsure of is if bike velocity and windspeed can be combined by simple addition to determine windchill "in motion", or if there is an exponential factor to consider as when two cars collide head on.
When two cars collide head on, each traveling at 15mph, the force of their collision is not the sum total of their combined velocities. Is it not the same when riding into a headwind?
Last edited by AllWeatherJeff; 01-17-20 at 05:59 PM.
#11
Non omnino gravis
If your relative velocity is slower than the windspeed, the wind is never going to be hitting you faster than the wind is blowing.
If the wind speed is 20mph and your speed is 10mph, the wind speed is 20mph.
If the wind speed is 10mph and your speed is 20mph, the wind speed is 20mph.
If the wind speed is 20mph and your speed is 10mph, the wind speed is 20mph.
If the wind speed is 10mph and your speed is 20mph, the wind speed is 20mph.
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^^please reconsider. If on a still day at 40F, you set out at 60 mph (back to my motorcycling example), you are going to be very, very cold.
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#13
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I can't help but think that you would rethink your reply if you'd ever ridden a bike at any speed into 25mph headwind in sub-freezing temperatures, and then compared that sensation by turning around and riding 25mph with a 25mph tailwind in the same temperature. The difference between the two experiences is immense.
Whether bare naked or buried beneath several winter layers, loss of heat is an inevitability in certain conditions, especially if one of the factors you have to consider before riding is how long you can last in the wind and sub freezing temperatures should you have to repair a flat tire far afield.
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AllWeatherJeff speed is not the same as momentum
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#15
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AllWeatherJeff speed is not the same as momentum
Are you saying that windchill is the same, regardless of whether or not one is moving or standing still?
This is the essence of my initial query.
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(Initially, I posted this query in the winter cycling sub-forum. But this sub-forum seems to get a lot more traffic)
If the temperature is 21°Farenheit and I'm cycling at 12mph into a 24mph headwind, is the windchill calculated using 36mph?
Similarly, if I'm traveling at 24mph with a 24mph tailwind is windchill negated?
If the temperature is 21°Farenheit and I'm cycling at 12mph into a 24mph headwind, is the windchill calculated using 36mph?
Similarly, if I'm traveling at 24mph with a 24mph tailwind is windchill negated?
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#17
Old Dog, New Tricks
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What is your experience of the difference between riding a motorcycle 60mph into a 25mph headwind versus riding 60mph with a 25mph tailwind?
#18
Old Dog, New Tricks
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Thanks. I wasn't sure if there was some kind of exponential factor of momentum nvolved as when two cars collide head on.
#19
Non omnino gravis
I can't help but think that you would rethink your reply if you'd ever ridden a bike at any speed into 25mph headwind in sub-freezing temperatures, and then compared that sensation by turning around and riding 25mph with a 25mph tailwind in the same temperature. The difference between the two experiences is immense.
Whether bare naked or buried beneath several winter layers, loss of heat is an inevitability in certain conditions, especially if one of the factors you have to consider before riding is how long you can last in the wind and sub freezing temperatures should you have to repair a flat tire far afield.
Whether bare naked or buried beneath several winter layers, loss of heat is an inevitability in certain conditions, especially if one of the factors you have to consider before riding is how long you can last in the wind and sub freezing temperatures should you have to repair a flat tire far afield.
Riding 25mph with a 25mph tailwind, wind speed 0mph.
And I reiterate: the wind speed is the wind speed; if you were to ride 25mph into a 25mph headwind, that doesn't magically make the wind speed 50mph. That's not how air works.
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according this calculator I was waaay off, should have been -1.3 degrees when I added wind speed against you with your traveling speed (36 mph wind against you). don't know why that wouldn't apply. but this is not my area of expertise. gotta explain it to me like I'm 6
https://www.weather.gov/epz/wxcalc_windchill
https://www.weather.gov/epz/wxcalc_windchill
Last edited by rumrunn6; 01-17-20 at 06:47 PM.
#21
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Riding 10mph into a 25mph headwind, wind speed 25mph.
Riding 25mph with a 25mph tailwind, wind speed 0mph.
And I reiterate: the wind speed is the wind speed; if you were to ride 25mph into a 25mph headwind, that doesn't magically make the wind speed 50mph. That's not how air works.
Riding 25mph with a 25mph tailwind, wind speed 0mph.
And I reiterate: the wind speed is the wind speed; if you were to ride 25mph into a 25mph headwind, that doesn't magically make the wind speed 50mph. That's not how air works.
I may be mistaken, but what sounds implausible is that your response implies that at 21°F with a 25mph wind that a body will lose heat at the same rate whether standing still or in motion.
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Merged duplicate thread. Please do not cross post.
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#23
Non omnino gravis
The windchill (relative) is as I said much earlier, around 5ºF, give or take. That's cold. If the wind chill were recalculated to say, -1ºF, would that make an earth-shattering difference?
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#24
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