Inspector Tools, Smoke Testing, Test-Kits and Safety Products
Meters, Test Kits, Inspection Equipment & Tools!
[ 0 Items | $0.00 | 0 lbs ]
Search Catalog:
Categories
Air Quality - IAQ

Carbon Monoxide (CO)

EMF / Microwave Meters

Fire and Smoke Safety

Food Safety & Hygiene

Gas and Leak Detectors

Heat Detector Testing

Light, LUX, UV Meters

Manometers / Pressure

Moisture Detectors

Radon Gas Testing

Radon Mitigation & Fans

Refractometers - BRIX

Smoke Trace Emitters

Soil & Grain Meters

Sound Level Meters

Specialty Instruments

Thermometers

Tools and Hardware

Videoscope Borescope

Water & Flood Alarms

Water Testing

Inspection Kits / Forms

Promotional Items
Customer Service
Customer Service
About Us
Shipping Policy
Return Policy
Privacy Notice
Conditions of Use
Contact Us
Heat Index Calculator

Heat Index, RH & Dew Point Calculator

Valid entries:
  • air temperatures greater than 80°F ( 27°C )
  • dew point temperatures greater than 60°F ( 16°C )
  • relative humidity higher than 40%
Calculate Heat Index and Relative Humidity by entering air Temperature and Dew Point

Enter air temperature ( Tair ) and Dew Point temperature ( Tdp ) in degrees. Click Calculate HI to compute heat index ( HI) and Relative Humidity ( RH ).

Tair in °F Tdp in °F RH =
Tair in °C Tdp in °C RH =
Calculate Heat Index and Dew Point by entering air Temperature and Humidity
Enter air temperature ( Tair ) and relative humidity ( RH ) without % sign. Click Calculate HI to compute heat index ( HI ) and Dew Point ( Tdp ).
Tair in °F RH % Tdp =
Tair in °C RH % Tdp =

What Is Heat Index?

Heat index (HI) is sometimes referred to as the "apparent Temperature". The HI, given in �F, is a measure of how hot it feels when relative humidity (RH) is added to the actual air temperature.

The following equation approximates the heat index. There are many assumptions made to produce this, far too many to list here. The equation was obtained by multiple regression analysis and there is a ±1.3 degree °F error.

HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 6.83783x10 -3 T 2
- 5.481717x10 -2 R 2 + 1.22874x10 -3 T 2R + 8.5282x10 -4 TR 2 - 1.99x10 -6 T 2 R 2
where
T = ambient dry bulb temperature degrees Fahrenheit
R = relative humidity
HEAT INDEX °F (°C)
  RELATIVE HUMIDITY (%)
Temp. 40 45 50 55 60 65 70 75 80 85 90 95 100
110
(47)
136
(58)
                       
108
(43)
130
(54)
137
(58)
                     
106
(41)
124
(51)
130
(54)
137
(58)
                   
104
(40)
119
(48)
124
(51)
131
(55)
137
(58)
                 
102
(39)
114
(46)
119
(48)
124
(51)
130
(54)
137
(58)
               
100
(38)
109
(43)
114
(46)
118
(48)
124
(51)
129
(54)
136
(58)
             
98
(37)
105
(41)
109
(43)
113
(45)
117
(47)
123
(51)
128
(53)
134
(57)
           
96
(36)
101
(38)
104
(40)
108
(42)
112
(44)
116
(47)
121
(49)
126
(52)
132
(56)
         
94
(34)
97
(36)
100
(38)
103
(39)
106
(41)
110
(43)
114
(46)
119
(48)
124
(51)
129
(54)
135
(57)
     
92
(33)
94
(34)
96
(36)
99
(37)
101
(38)
105
(41)
108
(42)
112
(44)
116
(47)
121
(49)
126
(52)
131
(55)
   
90
(32)
91
(33)
93
(34)
95
(35)
97
(36)
100
(38)
103
(39)
106
(41)
109
(43)
113
(45)
117
(47)
122
(50)
127
(53)
132
(56)
88
(31)
88
(31)
89
(32)
91
(33)
93
(34)
95
(35)
98
(37)
100
(38)
103
(39)
106
(41)
110
(43)
113
(45)
117
(47)
121
(49)
86
(30)
85
(29)
87
(31)
88
(31)
89
(32)
91
(33)
93
(34)
95
(35)
97
(36)
100
(38)
102
(39)
105
(41)
108
(42)
112
(44)
84
(29)
83
(28)
84
(29)
85
(29)
86
(30)
88
(31)
89
(32)
90
(32)
92
(33)
94
(34)
96
(36)
98
(37)
100
(38)
103
(39)
82
(28)
81
(27)
82
(28)
83
(28)
84
(29)
84
(29)
85
(29)
86
(30)
88
(31)
89
(32)
90
(32)
91
(33)
93
(34)
95
(35)
80
(27)
80
(27)
80
(27)
81
(27)
81
(27)
82
(28)
82
(28)
83
(28)
84
(29)
84
(29)
85
(29)
86
(30)
86
(30)
87
(31)

Category Heat Index Possible heat disorders for people in high risk groups
Extreme
Danger
130°F or higher
(54°C or higher)
Heat stroke or sunstroke likely.
Danger 105 - 129°F
(41 - 54°C)
Sunstroke, muscle cramps, and/or heat exhaustion likely. Heatstroke possible with prolonged exposure and/or physical activity.
Extreme
Caution
90 - 105°F
(32 - 41°C)
Sunstroke, muscle cramps, and/or heat exhaustion possible with prolonged exposure and/or physical activity.
Caution 80 - 90°F
(27 - 32°C)
Fatigue possible with prolonged exposure and/or physical activity.
Continue
Specials 
Manometer Digital 55.4" WC [-2 to 2 psi] Hi-Res (DM8252) RS232
Manometer Digital 55.4" WC [-2 to 2 psi] Hi-Res (DM8252) RS232
$259.99 $189.00
Indoor Air Quality Meter (AQM4) Measure CO, CO2, Temp & Humidity
Indoor Air Quality Meter (AQM4) Measure CO, CO2, Temp & Humidity
$695.95 $599.00
HSI CO Check (co8-TK3) Carbon Monoxide Detector Testing Kit
HSI CO Check (co8-TK3) Carbon Monoxide Detector Testing Kit
$31.50 $29.00
General Tools Electro-Magnetic Field Meter 0.1-199.9mGauss (EMF1390)
General Tools Electro-Magnetic Field Meter 0.1-199.9mGauss (EMF1390)
$99.95 $89.00
Megohmmeter: Digital Insulation Resistance Tester (DIT360) with Case
Megohmmeter: Digital Insulation Resistance Tester (DIT360) with Case
$299.00 $199.00
Versa-Test Heat Detector Tester Kit (VT694-16) w/16' Telescoping Pole
Versa-Test Heat Detector Tester Kit (VT694-16) w/16' Telescoping Pole
$999.95 $549.00
Welcome
Login:
eMail Address:
Password:
Forgotten Password?
Click Here
First Time Visitor?
Join Free
Specials more
Wall Ceiling Carbon Monoxide Alarm (MCN108) Battery Backup
Wall Ceiling Carbon Monoxide Alarm (MCN108) Battery Backup
$31.55 $29.00
Manufacturers
Dashboard
Radon Results Lookup
Carbon Monoxide Gas
CO Detector Badge
Conversion Calculators
Radon Gas Facts
Quick Find

Search Catalog:
Advanced Search
What's New? more
VOX-01 Voice Intelligibility Tester for STIPA Compliance Testing
VOX-01 Voice Intelligibility Tester for STIPA Compliance Testing
$2,145.00
  Your IP Address is: 54.92.170.149
Copyright Inspect USA®. All rights reserved. 1995-2018
No part of this website may be reproduced without our express consent.
InspectUSA.com - Distributors of TestKits, Inspection Tools, HVAC Smoke & Safety Equipment.
eMail with suggestions, product inquiries or comments. Thank you.
Customer Reviews