Custom Search
Over 10000 Pages Indexed
Your Host
Click here to read about RF CafeKirt
Blattenberger

... single-
handedly
redefining
what an
engineering website
should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5CCG (5th MOB):
My USAF radar shop

Hobby & Fun

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse
riding business website -
lots of info

•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Job Board

About RF Cafe©

RF Cafe E-Mail

Relative Humidity / Dew Point

The relative humidity of an air-water mixture is defined as the ratio of the partial pressure of water vapor in the mixture to the saturated vapor pressure of water at a prescribed temperature. Relative humidity is normally expressed as a percentage.

The dew point is the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dew point is a saturation point.

When the dew point temperature falls below freezing it is often called the frost point, as the water vapor no longer creates dew but instead creates frost or hoarfrost by deposition.

The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current air temperature. Relative humidity of 100% indicates that the dew point is equal to the current temperature (and the air is maximally saturated with water). When the dew point stays constant and temperature increases, relative humidity will decrease.

At a given barometric pressure, independent of temperature, the dew point indicates the mole fraction of water vapor in the air, and therefore determines the specific humidity of the air. - Wikipedia

Relative humidity of the air for temperature t and dew point d.
(from Smithsonian Meteorological Tables)

Relative Humidity (%)
Depression of
Dew Point t-d
-10°C 0°C +10°C +20°C +30°C
0.0 100 100 100 100 100
0.2 98 99 99 99 99
0.4 97 97 97 98 98
0.6 95 96 96 96 97
0.8 94 94 95 95 96
1.0 92 93 94 94 94
1.2 91 92 92 93 93
1.4 90 90 91 92 92
1.6 88 89 90 91 91
1.8 87 88 89 90 90
2.0 86 87 88 88 89
2.2 84 85 86 87 88
2.4 83 84 85 86 87
2.6 82 83 84 85 86
2.8 80 82 83 84 85
3.0 79 81 82 83 84
3.2 78 80 81 82 83
3.4 77 79 80 81 82
3.6 76 77 79 80 82
3.8 75 76 78 79 81
4.0 73 75 77 78 80
4.2 72 74 76 77 79
4.2 72 74 76 77 79
4.4 71 73 75 77 78
4.6 70 72 74 76 77
4.8 69 71 73 75 76
5.0 68 70 72 74 75
5.2 67 69 71 73 75
5.4 66 68 70 72 74
5.6 65 67 69 71 73
5.8 64 66 69 70 72
6.0 63 66 68 70 71
6.2 62 65 67 69 71
6.4 61 64 66 68 70
6.6 60 63 65 67 69
6.8 60 62 64 66 68
7.0 59 61 63 66 68
7.2 58 60 63 65 67
7.4 57 60 62 64 66
7.6 56 59 61 63 65
7.8 55 58 60 63 65
8.0 54 57 60 62 64
8.2 54 56 59 61 63
8.4 53 56 58 60 63
8.6 52 55 57 60 62
8.8 51 54 57 59 61
9.0 51 53 56 58 61
9.2 50 53 55 58 60
9.4 49 52 55 57 59
9.6 48 51 54 56 59
9.8 48 51 53 56 58
10.0 47 50 53 55 57
10.5 45 48 51 54  
11.0 44 47 49 52  
11.5 42 45 48 51  
12.0 41 44 47 49  
12.5 39 42 45 48  
13.0 38 41 44 46  
13.5 37 40 43 45  
14.0 35 38 41 44  
14.5 34 37 40 43  
15.0 33 36 39 42  
15.5 32 35 38 40  
16.0 31 34 37 39  
16.5 30 33 36 38  
17.0 29 32 35 37  
17.5 28 31 34 36  
18.0 27 30 33 35  
18.5 26 29 32 34  
19.0 25 28 31 33  
19.5 24 27 30 33  
20.0 24 26 29 32  
21.0 22 25 27    
22.0 21 23 26    
23.0 19 22 24    
24.0 18 21 23    
25.0 17 19 22    
26.0 16 18 21    
27.0 15 17 20    
28.0 14 16 19    
29.0 13 15 18    
30.0 12 14 17    

 

Information from CRC Handbook of Chemistry and Physics, 7first Edition, 1990-1991, David R. Lide



A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger
    KB3UON

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel