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Old 09-29-2010, 03:32 PM
 
Location: Perth, Western Australia
9,598 posts, read 15,016,836 times
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Quote:
Originally Posted by ChesterNZ View Post
Perhaps it's just a consequence of the fact that dry cold is more frequently experienced in continental regions while damp cold is more common in coastal regions and the former tends to be sunnier and less windy than the latter?

There doesn't seem to be any obvious scientific explanation for this, but I'm sure that, all else being equal, dry cold is more comfortable.
Have you ever felt colder on a cloudy day when it started off dry and turned to rain, and you go from dry to wet?

Obvious to me; condensation is like getting rained on if your out long enough.

I think anyone confused has not spent enough time (say most of the day or all day?) outdoors in cool/cold and variable weather.
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Old 09-29-2010, 04:40 PM
 
Location: Cloudchurch, Subantarctica
2,604 posts, read 1,771,958 times
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Quote:
Originally Posted by ColdCanadian View Post
Have you ever felt colder on a cloudy day when it started off dry and turned to rain, and you go from dry to wet?

Obvious to me; condensation is like getting rained on if your out long enough.

I think anyone confused has not spent enough time (say most of the day or all day?) outdoors in cool/cold and variable weather.
Doesn't your skin have to be below the dew point for condensation to form on it? I don't see that happening outside of Singapore and the like!
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Old 09-29-2010, 05:05 PM
 
Location: Perth, Western Australia
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Quote:
Originally Posted by ChesterNZ View Post
Doesn't your skin have to be below the dew point for condensation to form on it? I don't see that happening outside of Singapore and the like!
For your skin to be below the dewpoint, you'd have to have some serious medical problems.

No, but if any part of the air touching you that is at or below the dewpoint, it will make you damp in that spot.
Just look at a parked car or green grass at night and you'll see air is seldom the same temperature everywhere.

Also evaporation with wind lowers air temp slightly in localised areas,
so high RH% could mean high probability of extra water being evaporated.

Touching objects that are at or below the dewpoint will also make you slightly wet/damp which adds some more chill.

Water also has capilary force, so as beads of water get thinner, they have more spreading force, like travelling up the underside of an angled roof. It's how trees get water from the ground to their canopy without having a "water pump." This capillary force could affect people's comfort, with wetness covering more surface area of your body than what intuitively makes sense.
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Old 09-29-2010, 08:50 PM
 
Location: New York City
2,792 posts, read 2,725,728 times
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Quote:
Originally Posted by ColdCanadian View Post
For your skin to be below the dewpoint, you'd have to have some serious medical problems.

No, but if any part of the air touching you that is at or below the dewpoint, it will make you damp in that spot.
Just look at a parked car or green grass at night and you'll see air is seldom the same temperature everywhere.

Also evaporation with wind lowers air temp slightly in localised areas,
so high RH% could mean high probability of extra water being evaporated.

Touching objects that are at or below the dewpoint will also make you slightly wet/damp which adds some more chill.

Water also has capilary force, so as beads of water get thinner, they have more spreading force, like travelling up the underside of an angled roof. It's how trees get water from the ground to their canopy without having a "water pump." This capillary force could affect people's comfort, with wetness covering more surface area of your body than what intuitively makes sense.
Your body will warm the air before condensation can occur. In fact, there is a micro layer (micrometers thick) of warm air around you all the time. It is the wind that strips it off (parts not covered by clothes, anyway).
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Old 09-30-2010, 04:47 PM
 
Location: Perth, Western Australia
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Quote:
Originally Posted by MrMarbles View Post
Your body will warm the air before condensation can occur. In fact, there is a micro layer (micrometers thick) of warm air around you all the time. It is the wind that strips it off (parts not covered by clothes, anyway).
You don't understand.

If condensation is in the air and you go for a walk,
as you are walking by the air your body doens't have enough time to warm the air;
in essence you are walking through a light fog.
Same thing if you are standing still, and it is windy and humid.

Condensation often occurs on fine particles in the air, dust and what-not.
It's not like without you being there and a skin or clothing temp at or below the dewpoint, condensation won't form.

The only chance I see of staying dry is having a skin temp of 200+ F; standing by you is like standing by a barbeque!
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Old 10-04-2010, 07:12 PM
 
Location: Two Rivers, Wisconsin
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I can't get technical, but I've always said, damp cold bothers me way more than dry cold. Forties, fog, drizzle can be more miserable than the 30's, sunshine and a dry day.

For me, nothing to do with what clothes I have on, living in the midwest all my life, near the lake, I always dress for the weather and I'm always prepared.
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Old 10-04-2010, 07:51 PM
Status: "Only 2 puppies of 11 left to sell." (set 13 days ago)
 
Location: Beautiful Niagara Falls ON.
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I have lived all my life in a damp wet cold place. Southern Ontario Canada. Now I have to tell you that I thought those folks from really cold places like Winnipeg were full of BS. They would claim that it was worse in Toronto at 32f or 0c than it was out west at - 30 F or C. Well I found out for myself they were right. Last winter my wife and I plus or two little furballs were in North Dakota one day and it was -40 C. Now that's cold, ya gotta admit. The furry boys and I off we go for a walk and oh ya I forgot to tell ya that the wind was blowin at about 40 knots or so too. Well we were out there for a hour or so trudging through the snow and I had sweat running down my back. The boys seemed OK too but their little furry feet were cold. Mine probably would have been too but I had boots on mine. Anyway it's true the dry cols just does not seem to go through you like the damp cold does. I worked for a couple of winters up in the far north and it was bone dry. We worked outside and we got to go home for the day with full pay when it dipped below -50f. I think they had the thermometer rigged because it just seemed to get stuck around -48 or so. Anyway I was always warm anyway but I looked like the Michlen man I was so padded up with down coats vests jackets hats gloves and boots. At -50 a big dump truck would go by a raise a cloud of snowy dust that would just hang there in the air for half an hour or so. With the sun shining through that snowy dust it looked like the air was full of diamonds sparkeling. That major dry cold. I love it and can't wait to be in some this winter. The furry boys though they have decided to take a pass on it and I have to throw them out of the truck to take their pee.
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Old 10-04-2010, 09:20 PM
 
Location: New York City
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Found this online that agrees with what I've been saying before:
USATODAY.com

Quote:
Q: Does humid air make cool weather feel cooler?
A: The amount of humidity in the air by itself doesn't make any difference in how cold the air "feels." Sometimes you will hear that the water vapor in the air carries heat away, cooling you faster. At first glance that might seem to make sense because most people have heard of victims of boating accidents dying because they weren't pulled from chilly water before dying of hypothermia -- a cooling of the body's core temperature. In these cases the water does quickly carry heat away from the body and people with no protection can die quickly in 40-degree water. But, even on the most humid of days, especially when the air is chilly, the percentage of water molecules in the air as water vapor is very small. Even if water molecules did carry heat away from your body, there are too few to noticeably cool you. Also, it turns out that water vapor molecules are no better at conducting heat than the nitrogen and oxygen molecules that make up most of the air.
What I have to say here is based on the "Water Vapor Mysticism" chapter in a delightful book, What Light Through Yonder Window Breaks: More Experiments in Atmospheric Physics by Craig F. Bohren, published by John Wiley & Sons, Inc. in 1991. In it, he not only gives the theoretical arguments in the paragraph above, but also describes some simple, home experiments to show things don't cool faster in cool but humid air than in cool but dry air.
Why do people think wet cold is more uncomfortable than dry cold? Bohren's answer makes sense to me. Humid places are often cloudy. A cold, sunny day doesn't feel as chilly as a cold, cloudy day because even as the air is cooling us, direct sunlight is warming us. The USATODAY.com Understanding water in the atmosphere page has links to a lot more on how water in all of its forms affect the weather.
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Old 10-05-2010, 09:01 AM
 
Location: Western Massachusetts
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Meh. In winter, or at least December or January, the sun isn't high enough in the sky to cause a noticeable warming effect for most of the day.
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Old 10-05-2010, 10:35 AM
 
Location: USA East Coast
4,445 posts, read 4,440,309 times
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Quote:
Originally Posted by nei View Post
Meh. In winter, or at least December or January, the sun isn't high enough in the sky to cause a noticeable warming effect for most of the day.
Imagine how the people in Europe, Russia, or Canada feel.

90% of the USA mainland is south of 43 north latitude…places like England, Ireland, Germany, Poland, Russia…etc are above 50 north latitude. London or Moscow are more than 700 miles north of most cities in the USA like San Francisco (38 N) or NYC (40 N). The sun angle at 35 or 40 latitude even on December 21st...has a signifcant warming effect.
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