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Konstantinos

What's On The Thermometer And What You Actually Feel

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How do I calculate the real feel of temperature if I know the temperature out of my house, the external humidity and the air pressure? Is there a mathematical formula?

For example now the temperature out of my house is 19.5 degrees C, the external humidity 61% and the air pressure 990 mb. So, how is the real feel of temperature out of my house?

Thank you.

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its a very long calculation... so use NOAA's heat index calculator.

http://www.hpc.ncep....heatindex.shtml

it says fills like temperature of 19c still?

Ok this is very good. Thank you. So now, the real feel of the temperature out of my house is 19 degrees C.

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Ok this is very good. Thank you. So now, the real feel of the temperature out of my house is 19 degrees C.

It must be alot more humid here then cause my temp is 18.4C 90% humidity and heat index of 19C aswel!

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It must be alot more humid here then cause my temp is 18.4C 90% humidity and heat index of 19C aswel!

What about 90% humidity in your region? Is it raining?

I think you need more temperature there. For example 28C 90% humidity implies heat index 34 C.

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What about 90% humidity in your region? Is it raining?

I think you need more temperature there. For example 28C 90% humidity implies heat index 34 C.

of course not although i can see that mist is starting to form so thats probably why?

Dew Points are 17C here still and its 1am!

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But when we are trying to find what the "feel like factor" is aren't there other things coming into play, such as the wind speed? Then when we get down to temperatures near freezing doesn't the energy of 80 cals per cc come into play when water is freezing or ice melting. I know it is now a long time ago but I was taught that heat and temperature are not the same thing and that heat is the total calorific value of the energy whilst temperature is merely the the level.

I get the impression that the human body reacts more to the actual heat rather than the temperature but my understanding of all this is a little hazy and I would also like to understand this in greater detail.

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The Heat Index (HI) is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature - how hot it feels, termed the felt air temperature.

The human body normally cools itself by perspiration, or sweating, which evaporates and carries heat away from the body. However, when the relative humidity is high, the evaporation rate is reduced, so heat is removed from the body at a lower rate causing it to retain more heat than it would in dry air. Measurements have been taken based on subjective descriptions of how hot subjects feel for a given temperature and humidity, allowing an index to be made which corresponds a temperature and humidity combination to a higher temperature in dry air.

The heat index is derived from work carried out by R. G. Steadman. Like the wind chill index, the heat index contains assumptions about the human body mass and height, clothing, and the wind speed. Significant deviations from these will result in heat index values which do not accurately reflect the perceived temperature.

At high temperatures, the level of relative humidity needed to make the heat index higher than the actual temperature is lower than at cooler temperatures. For example, at 27°C (approximately 80°F), the heat index will agree with the actual temperature if the relative humidity is 45%, but at 43°C (roughly 110°F), any relative humidity reading above 17% will make the Heat Index higher than 43°C. Humidity is deemed not to raise the apparent temperature at all if the actual temperature is below approximately 20°C (68°F) essentially the same temperature colder than which wind chill is thought to commence. Humidex and heat indexes are based on temperature measurements taken in the shade and not the sun, so extra care must be taken while in the sun.

Sometimes the heat index and the wind chill factor are denoted collectively by the single terms "apparent temperature" or "relative outdoor temperature."

Outdoors in open conditions, as relative humidity increases, first haze and ultimately thicker cloud cover develops, reducing the amount of direct sunlight reaching the surface; thus there is an inverse relationship between maximum potential temperature and maximum potential relative humidity. Because of this factor, it was once believed that the highest heat index reading actually attainable anywhere on Earth is approximately 71°C (160°F). However, in Dhahran, Saudi Arabia on 8 July 2003, the dewpoint was 35°C while the temperature was 42°C. The heat index at that time was 78°C.

A good example of the difference between heat index and true temperature would be comparing the climates of Miami and Phoenix. Miami averages around 35°C in summer due to the easterly trade winds coming from the Atlantic Ocean, but it has a high humidity (e.g. 75%). Phoenix averages around 40°C in summer, but typically has a low humidity (e.g. 10%). According to the heat index, the relative temperature in Miami will be 44°C, but the relative temperature in Phoenix will be lowered due to the lower humidity, to around 37°C. Given sunshine, Miami is likely to feel hotter than Phoenix.

http://www.southampt...k/heatindex.php

post-6667-0-74472400-1337945714_thumb.jp

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How do you feel the temperature outside to what is showing on the thermometer?

I find myself sticking to a jumper when most others are in a t-shirt and shorts, i feel the cold easily and am very sensitive to temperature changes, in the colder months i'm usually the one wearing the coat for longest, and in summer i'm last to put the jumper away.

It does depend on a variety of things and not just what the thermometer reads, this could be the wind direction, the speed, and what type of cloud there is.

it's quite often through summer when we get cooler weather with warm sunshine i see myself looking like the next arctic front is sweeping through, i'm in a jumper and jeans sometimes a coat! and everyone else is in t-shirt and shorts, so are those people warm? or is it just because it's summer so they have to wear those clothes? or why am i feeling so cold! i do find that i freeze on frosty nights even wrapped up well and with gloves, where's hardly any one i see wears gloves even in snow.

So everyone feels the air temperature differently, the thermometer can't always tell me to wear a jumper, can the weather forecast on the tv tell me to leave the jumper at home? rofl.gif ..sometimes i just have to go outside to feel it!

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I find humidity to be a large factor.

Today's it's 14.2c with 82% humidity, felt very comfortable stepping out into it. Whereas yesterday's humidity was much lower and stepping

out when the sun was covered by cloud with it 15c+ was cool feeling - however once the cloud cleared the summer sun warmth took over!

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There have been quite a few mornings lately when i've looked at the temperature and its only read something like 12/13c which has given me the impression that it must be cold. However, upon stepping outside i have found that its actually quite pleasant and a just a t-shirt would be appropriate.

Something i have also noticed is that on a cold winters day with plentiful sunshine i can find it pleasant being out in just a t-shirt despite the air temperature only being 3/4c. Thats if there is almost no wind. Thinking about those temperatures at the moment makes me feel like that must definately be coat, hat and gloves weather. But i guess it depends on what you are doing. Those sort of temperatures would require several layers if going to watch the football, but just one layer if i was out in the garden for a short time.

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I'm usually last to put any kind of coat/jumper on compared to near enough everyone I know (yes despite my constant warm yapping I don't feel the cold that much! But then I don't mind heat either).

But walking or cycling around I quickly warm up so it's t-shirt weather for me 12c or above (unless it rains).

The times I get most cold is actually coolish evenings where its been nice, warm & sunny all day and you then head to the pub and sit outside. But unless temps are still well up in the 20s you quickly chill as the sun is blocked by buildings and then just cannot warm up. Hence the need for proper warm evenings for which higher humidity is a real bonus.

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I've worked outdoors all my life and can tolerate/endure anything the British climate cares to offer but I cannot abide sitting indoors in a chilly draught, even if the indoor temperature is around

17c.

The wind chill factor is the over riding factor in how comfortable the air feels in my opinion. I've felt colder in mid July working in a temperature of 14c with a 30 mph wind than I have in January with a temperature of 3c and no wind.

Being wet is also guaranteed to make you feel cold quicker, and being wet in combination with a strong wind is positively miserable.

Aside from all that I'd rather be too cold than too hot and, within the parameters of all the weather I've experienced so far in my life, you'll never hear me complaining of the cold no matter what the time of year.

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its all to do with humidity i find 21c feels much warmer in the UK than it does here in Canada..and also -5c feels much colder in the UK.

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Humidity makes heat feel hotter and tends to make cold feel colder.. for example, a damp, cloudy -5C in Toronto probably feels colder than a dry, sunny and windless -10C in Calgary.

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It is obviously subjective to some degree.I have noticed that simply the amount of food I have had has a great influence on how I "feel" the temperature.This only really applies when ,in the past,I had not eaten anything or very little for days;with very little body fat and no energy I would feel the cold a lot more than others.

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Yes being hungry or tired makes you cold for definite. No surprise really as you're lacking the energy needed to maintain body temperature.

For that reason you need less sleep & food in warmer weather and considerably more in cold & dark winter conditions.

I know I eat far more chocolate & greasy stuff November-February than I do at other times of year.

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I have a very fast metabolism, so just about the only time Im ever cold is when Ive just woken up and not eaten yet, once Ive had my first meal of the day I warm up quite rapidly, which is a big problem in winter as Ill set the heating so the house is warm when I get up (around 21C), then spend the rest of the morning too warm once Ive had my breakfast! Myself and the wife quite often argue about it as shes always cold, even in the height of summer. On nights with min temps of 18C she'll be in bed with two layers on while I lay there awake on top of the covers (yes not a sheet) dripping with sweat.

Unsuprisingly I dont cope well in heat at all. I can handle temperatures up to about 25C if there is a strong breeze, but in calm conditions I start to melt not much above 20C. As for the cold, I didnt even need a jumper in December 2010 when I went to work one morning and it was -11.4C.

I do agree with TM though, from 2001-2007 I used to work outside for a living and can remember there was a day where the air temperature was 3C but there was a sustained 40mph wind gusting to 60-70mph. Ive never felt so cold in my life. August 2003 was awful too however, I was outside for 4 consecutive days during the warmest part of the spell (bearing in mind it didnt get above 31C here, so not that severe compared to further south) and ended up off after that with heatstroke.

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Yes being hungry or tired makes you cold for definite. No surprise really as you're lacking the energy needed to maintain body temperature.

For that reason you need less sleep & food in warmer weather and considerably more in cold & dark winter conditions.

I know I eat far more chocolate & greasy stuff November-February than I do at other times of year.

I eat chocolate & greasy stuff all the time :p

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I have a very fast metabolism, so just about the only time Im ever cold is when Ive just woken up and not eaten yet, once Ive had my first meal of the day I warm up quite rapidly, which is a big problem in winter as Ill set the heating so the house is warm when I get up (around 21C), then spend the rest of the morning too warm once Ive had my breakfast! Myself and the wife quite often argue about it as shes always cold, even in the height of summer. On nights with min temps of 18C she'll be in bed with two layers on while I lay there awake on top of the covers (yes not a sheet) dripping with sweat.

Unsuprisingly I dont cope well in heat at all. I can handle temperatures up to about 25C if there is a strong breeze, but in calm conditions I start to melt not much above 20C. As for the cold, I didnt even need a jumper in December 2010 when I went to work one morning and it was -11.4C.

I do agree with TM though, from 2001-2007 I used to work outside for a living and can remember there was a day where the air temperature was 3C but there was a sustained 40mph wind gusting to 60-70mph. Ive never felt so cold in my life. August 2003 was awful too however, I was outside for 4 consecutive days during the warmest part of the spell (bearing in mind it didnt get above 31C here, so not that severe compared to further south) and ended up off after that with heatstroke.

I recall walking my dog during the December 2010 cold spell when the temperature was below freezing - only needed sweat pants and a light jacket, no big deal, no scarfs, gloves or woolies needed at all.. however, I definitely would need to wrap up during the recent wet weather, for example, when the temperature did not exceed 8C during the day at all with constant heavy rain. I feel much, much colder walking in rain than snow.

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I've worked outdoors all my life and can tolerate/endure anything the British climate cares to offer but I cannot abide sitting indoors in a chilly draught, even if the indoor temperature is around

17c.

The wind chill factor is the over riding factor in how comfortable the air feels in my opinion. I've felt colder in mid July working in a temperature of 14c with a 30 mph wind than I have in January with a temperature of 3c and no wind.

Being wet is also guaranteed to make you feel cold quicker, and being wet in combination with a strong wind is positively miserable.

Aside from all that I'd rather be too cold than too hot and, within the parameters of all the weather I've experienced so far in my life, you'll never hear me complaining of the cold no matter what the time of year.

Some very mild tm airmasses in winter we get can bring the temperature up to something like 15C or even higher, and this can make it feel warm after such cold weather, and back in Feb when we had a warm spell i was taking my coat off, it was sunny, wheres last summer on an August afternoon we had a cool northeast wind and overcast, i was in a jumper and coat and felt chilly. So it is to do with what you are used to as well as the wind chill, a cool cloudy northeasterly on a summer day is the worst and most annoying one! in some setups with a flow from the ne in summer it can start clear and sunny and then the cloud builds and flatterns out to form a layer of cloud and really spoils the day that started so sunny! stratocumulus i think it is.

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Interesting posts.

Food type we eat can make a difference to, and in the hot spells we burn up the calories faster.

Another thing that makes a diffrence to how i feel in winter cold is if it's cold for a reason, if it's a nice frost or snow then i can feel a bit warmer then if there is boring cold cloudy weather... maybe it's just because i like the frost and snow so being excited makes me feel warmer.

Does anyone get this effect?

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Other contributory factors might be subliminal information; those little things that affect our emotional state without necessarily being consciously recognized?

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