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

Anemometers-Air Flow

Carbon Monoxide (CO)

EMF / Microwave Meters

Fire and Smoke Safety

Food Safety & Hygiene

Gas and Leak Detectors

Heat Detector Testing

Infrared Thermometers

Inspection Supplies

Light, LUX, UV Meters

Manometers / Pressure

Moisture Detectors

Power & Circuit Testers

Radon Mitigation & Fans

Radon Testing & Supplies

Refractometers - BRIX

Safety and Security

Smoke Trace Emitters

Soil & Grain Meters

Sound Level Meters

Specialty Instruments

Temperature & Humidity

Timers and Clocks

Tools and Hardware

Water & Flood Alarms

Water Testing

Clearance
Customer Service

About Us

Shipping Policy

Return Policy

Privacy Notice

Conditions of Use

Contact Us
Manufacturers
Radon Results Lookup
Carbon Monoxide Gas
Conversion Calculators
Copyright & Trademark
Heat Index Calculator

Calculate Heat Index and Relative Humidity by entering air Temperature and Dew Point

Valid entries:
  • air temperatures greater than 80°F ( 27°C )
  • dew point temperatures greater than 60°F ( 16°C )
  • relative humidity higher than 40%

Heat Index, RH and Dew Point Calculator

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  degreesF, 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 
Indoor Air Quality Meter Logging (PM-1063SD) Measure PM2.5, Temp & RH
Indoor Air Quality Meter Logging (PM-1063SD) Measure PM2.5, Temp & RH
$499.95 $395.00
Leica Laser Line Level (L2) with Target Plate, Adapter, Tripod & Case
Leica Laser Line Level (L2) with Target Plate, Adapter, Tripod & Case
$279.95 $195.00
Delmhorst ProScan Non-Invasive Pinless Moisture Meter with Case
Delmhorst ProScan Non-Invasive Pinless Moisture Meter with Case
$425.00 $399.00
Versa-Test Enclosed Delivery Kit (VT-KIT-1) with 4' & 16' Poles
Versa-Test Enclosed Delivery Kit (VT-KIT-1) with 4' & 16' Poles
$999.99 $749.00
Solo Smoke Detector Tester (Sabre) with 8" Extension Wand
Solo Smoke Detector Tester (Sabre) with 8" Extension Wand
$10.95 $8.99
Lutron Pen Type Vibration Meter (PVB-820) with Magnetic Mount
Lutron Pen Type Vibration Meter (PVB-820) with Magnetic Mount
$299.95 $272.50
Analog Fiber Optic Borescope 0.4" x 18" (VO18-10WW) Obedient Shaft
Analog Fiber Optic Borescope 0.4" x 18" (VO18-10WW) Obedient Shaft
$239.00 $199.00
PurCheck Non-Flammable Smoke Detector Test Spray (30s) HSI 4.6oz
PurCheck Non-Flammable Smoke Detector Test Spray (30s) HSI 4.6oz
$16.95 $12.99
Heat Detector Test Head Kit Wireless (SOLO 461) w/Batteries & Charger
Heat Detector Test Head Kit Wireless (SOLO 461) w/Batteries & Charger
$1,247.95 $975.00
USI CO & Natural Gas Alarm (MCN400) Battery Backup 7/3/2013
USI CO & Natural Gas Alarm (MCN400) Battery Backup 7/3/2013
$39.99 $20.00
Versa Open Delivery Extension Pole Aluminum 50" (N59) Use with N30 Head
Versa Open Delivery Extension Pole Aluminum 50" (N59) Use with N30 Head
$259.99 $199.00
5-in-1 Airflow Meter (ABH-4225) Temp, RH, Dew Point & Pressure
5-in-1 Airflow Meter (ABH-4225) Temp, RH, Dew Point & Pressure
$159.95 $129.00
Crank Style Insulation Resistance Tester (IRT20) Megohmmeter
Crank Style Insulation Resistance Tester (IRT20) Megohmmeter
$375.00 $359.00
Eagle Analog BoreScope (PV300E) 36 x 0.4 inch SS Flexible Shaft
Eagle Analog BoreScope (PV300E) 36 x 0.4 inch SS Flexible Shaft
$349.95 $225.00
Custom Printed Carbon Monoxide Detector Badge (CP300) Limited Offer
Custom Printed Carbon Monoxide Detector Badge (CP300) Limited Offer
$995.00 $825.00
Lutron 3-Axis Low & High Frequency EMF Meter (EMF-839) with 2 Probes
Lutron 3-Axis Low & High Frequency EMF Meter (EMF-839) with 2 Probes
$1,049.00 $995.00
Digital Soil pH Meter 0-14 pH (PH-212HD) with HD Spear Tip Soil Probe
Digital Soil pH Meter 0-14 pH (PH-212HD) with HD Spear Tip Soil Probe
$299.95 $235.00
Auto-Ranging Lux or FootCandles Light Meter (TM203) Datalogging
Auto-Ranging Lux or FootCandles Light Meter (TM203) Datalogging
$299.99 $199.00
Lutron Noise Dosimeter (DS-2013SD) with SD Card Data Logging
Lutron Noise Dosimeter (DS-2013SD) with SD Card Data Logging
$599.95 $449.00
Flexible Coupling 4 x 6 WHITE (79039) with SS Heavy Duty Clamps
Flexible Coupling 4 x 6 WHITE (79039) with SS Heavy Duty Clamps
$20.95 $18.95
Leica Red Lens Glasses (723777) Improves Visibility of Laser Dot
Leica Red Lens Glasses (723777) Improves Visibility of Laser Dot
$29.99 $12.95
Welcome
Login:
eMail Address:
Password:
Forgot Password?
Password Reset
First Time Visitor?
Join Free
Specials more
General Tools Eyeglass Repair Kit (601) with Screw Assortment & Tool
General Tools Eyeglass Repair Kit (601) with Screw Assortment & Tool
$1.99 $1.00
Manufacturers
Quick Find

Search Catalog:

Advanced Search
What's New? more
Systems Fire Alarm Document Box (SSU00672) Red 12"x13" Steel
Systems Fire Alarm Document Box (SSU00672) Red 12"x13" Steel
$79.00
  Your IP Address is: 18.234.88.196
Copyright Inspect USA®. All rights reserved. 1995-2019
No part of this website may be reproduced without our express consent.
Distributors of TestKits, Inspection Tools, HVAC Smoke & Food Safety Equipment.
Customer Reviews Click for the BBB Business Review of this Mail Order & Catalog Shopping in Marshall NC