what is a simple way to calculate dew point using temperature and relative humidity?
610505
Simple?  I'm not sure.  However, here's a formula from the following web page\n\nfunction Dewpoint(calcDewpoint) {\n  var t, f, dewpoint;\n  if (calcDewpoint.Radio1[0].checked == true) {\n   t = convert2C(calcDewpoint.T.value);\n  }else {\n      t = parseInt(calcDewpoint.T.value);\n  }\n  f = parseInt(calcDewpoint.RH.value)/100;\n  dewpoint = 237.3/(1/(Math.log(f)/17.27+t/(t+237.3))-1);\n  calcDewpoint.DPC.value = (Math.round(dewpoint));\n  calcDewpoint.DPF.value = Math.round((dewpoint * 9/5) + 32);\n}\n\nLawrence
781580
I live in Virginia too.  The answer can be described in two words.  Low dewpoint.  In the summer, you have temps in the 90s and dewpoints in the 70's, making it muggy overnight.  This time of year, the dewpoint is very low, in the 30's and 40's.  The sun is the only thing that holds the temp up.   The humidity is lower in the daytime and higher at night.  It is all about the dewpoint. The higher the dewpoint, the worse it feels to your skin.  The dewpoint can also be too low too.  Making your skin very dry.  I like that because you have a different variety of temps in the same day.  If you like warm weather, go out in the middle of the day. If you like cold weather, go out near dusk.  You have your choice.
388380
None of the above.  The amount of moisture in an air mass is relative.  "Very little moisture" tells us nothing about the temperature, dew point or stability of an air mass which are the determining factors for cloud formation.
976898
P1V1/T1 = P2V2/T2\nP1 = 1 atmosphere = 101325 N / (m^2)\nV1 = (4*10^3 cm^3)(1 m^3/10^6 cm^3) = 4*10^-3 m^3\nP2 = P1 + h*2.00103/0.01\nV2 = V1 + 0.01h\nT1 = 20°C = 293.15°K\nT2 = 260°C + 273.15 = 533.15°K\nA = 0.01 m^2\nP1V1/T1 = (P1 + hk)(V1 + Ah)/T2\nP1V1/T1 = P1V1/T2 + ((kV1 + AP1)h + kAh^2)/T2\nP1V1(T2 - T1)/T1 = (kV1 + AP1)h + kAh^2 \nkAh^2 + (kV1 + AP1)h - P1V1(T2 - T1)/T1\nh^2 + ((kV1 + AP1)/kA)h - P1V1(T2 - T1)/(kAT1)\n((kV1 + AP1)/kA) = ((2.00103*4*10^-3 + 0.01*101325))/(2.00103*0.01)\n((kV1 + AP1)/kA) = 50636.82\nP1V1(T2 - T1)/(kAT1) = (101325)(4*10^-3)(533.15 - 293.15)/(2.00103*0.01*293.15)\nP1V1(T2 - T1)/(kAT1) = 16582.28\nh = (- 50636.82 ± √(50636.82^2 + 4*16582.28))/2\nh = - 25318.41 ± √(25318.41^2 + 16582.28)\nh = - 25318.41 ± 25318.74\nh = 0.34 m = 340 cm\n\nb)\nP2 = 101,325 + 0.34*2.00103/0.01\nP2 = 101,393 N/m^2
548046
To an extent it is true.  If dew has settled by morning, then that means there is less water vapor in the air.  If there is less water in the air, then it is less likely to condensate and fall.  However, after dew has settled, if it gets cold enough, it can still rain.
767105
While the math gets a bit complex, relative humidity cannot naturally reach zero percent on the Earth's surface.  Even in Las Vegas, one of the driest places on earth, the relative humidity runs about 11% on a June afternoon.  The lowest relative humidity ever recorded anywhere on Earth was about 2%.  So, no, it is not possible to reach zero percent relative humidity other than in a laboratory.\n\nAnywhere you have fog or rain, you generally have 100% relative humidity, so this is quite a common condition everywhere.
144194
Yes.. It's called heat index..\n--------------------------------------\nThe heat index (HI) or humidex is an index that combines air temperature and relative humidity to determine an apparent temperature — how hot it actually feels. The human body normally cools itself by perspiration, or sweating, in which the water in the sweat evaporates and carries heat away from the body. However, when the relative humidity is high, the evaporation rate of the water is reduced. This means 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.\n\nAt 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 80 °F (approximately 27 °C), the heat index will agree with the actual temperature if the relative humidity is 45%, but at 110 °F (roughly 43 °C), any relative-humidity reading above 17% will make the Heat Index higher than 110 °F. Humidity is deemed not to raise the apparent temperature at all if the actual temperature is below approximately 68 °F (20 °C) — essentially the same temperature colder than which wind chill is thought to commence.\n\nAs relative humidity increases, however, first haze and ultimately thicker cloud cover must develop, reducing the amount of direct sunlight reaching the surface; thus there is an inverse relationship between maximum potential temperature and maximum potential relative humidity, therefore making, say, a simultaneous temperature of 120 °F (50 °C) and 90% relative humidity physically impossible. Because of this factor, it is believed that the highest heat-index reading actually attainable anywhere on Earth is approximately 160 °F (70 °C) in the shade that is 172 °F (78 °C) in the sun.\n\nA good example of the difference between heat index and true temperature would be comparing the climates of New Orleans, Louisiana and Bakersfield, California. New Orleans has lower heat temperatures due to being closer to the Gulf of Mexico, yet the city has a higher heat index because it is a humid heat. Likewise, while Bakersfield actually has hotter daytime temperatures, Bakersfield has a dry heat, so it doesn't feel as hot.\n\nSometimes the heat index and the wind chill factor are denoted collectively by the single terms "apparent temperature" or "relative outdoor temperature".\n\nA typical measurement in the United Kingdom in the hottest areas in the hottest type of weather generally has temperatures that can get above about 90 °F (32 °C) in the shade with 50% humidity which on the humidex chart is 104 °F (40 °C) in the shade and 119 °F (48 °C) in the sun. You should note that humidex and heat indexes are taken in the shade and not the sun; so extra care must be taken while in the sun! For the record, temperatures reached 101.3 °F (38.5 °C) in Kent in mid August 2003 which is the national record; assuming that this was 50% humidity; it would have a humidex of 126 °F (52 °C) in the shade and 140 °F (60 °C) in the sun. Of course in such extreme heat, the likelihood is that the humidity fell and the humidex was not quite that high.\n\nWARNING - Add approximately 15 °F (8 °C) to the heat index for measurements in direct sunshine.\n \nEffects of the heat index (shade values)\nFahrenheit Celsius Notes \n80–90 °F 27–32 °C Caution — fatigue is possible with prolonged exposure and activity \n90–105 °F 32–41 °C Extreme caution — sunstroke, heat cramps, and heat exhaustion are possible \n105–130 °F 41–54 °C Danger — sunstroke, heat cramps, and heat exhaustion are likely; heat stroke is possible \nover 130 °F over 54 °C Extreme danger —
304701
3°C\nFeels like : -3°C \nRelative humidity : 93% \nWind : 31 km/h N \nBarometric pressure : 100.7 kPa  \nDewpoint : 2°C
100101
Use a calculator, add all three together (be sure to include the negatives) and then multiply by the number of temperatures.
893197
Try a histogram and use a range of temperatures.
740779
use pv=nrt and you can get the answers
958888
Use the formula:\nQ (heat) = Cp (Heat Capacity) * delta T (Change in Temperature)
501191
There is a formula...but this is much easier\n\nhttp://www.onlineconversion.com/temperature.htm
1165990
http://www.temperatures.com/apps/index.html
560715
If you mean on the surface, then yes. There is a big misconception about this.\n\nIt needs to be 100% relative humidity where clouds are developing NOT on the surface.\n\nThe dew point is the temperature at which saturation occurs (100% humidity). When the dew point is reached at cloud condensation level, then clouds will form & precipitation may occur.\n\nHumidity is measured in several different ways. Relative humidity is how much water vapor compared to how much it could hold at a certain temperature. This is the one we use most often.
800910
Typically between -20 and +10 degrees Celcius (-4 to +50 F). It depends very much on the amount of humidity in the air. If it is very humid you will start see it at higher temperatures than usual. That's because the air can only contain a certain amount of water vapour at a certain temperature and when the amount of water vapour increases that value the water will condense into liquid water and that's what you see when you "see you breath". The temperature you are referring to is called the dew point and can be found in advanced weather forecasts.
56557
Abrupt vertical growth on clouds and/or thick cloud layers...   Winds at the surface are typically more southerly just ahead of a cold front and strong temperature and dewpoint discontinuities are found along cold frontal boundaries.  For instance if you're sitting at 49 degrees with a dewpoint of 41, and a city/town west or northwest of you is sitting at 33, with a dewpoint of 17 - most likely you'll have a cold front between you.  Certainly, not always the case, but is generally true.  Your dewpoint depression (the value of your dewpoint subtracted from your temperature) is also typically less than that found behind a cold front.