ARL‐SR‐0317 ● MAR 2015

US Army Research Laboratory

Wet‐Bulb–Globe Temperature Data Report

by David P Sauter

Approved for public release; distribution unlimited
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ARL‐SR‐0317 ● MAR 2015

US Army Research Laboratory

Wet‐Bulb–Globe Temperature Data Report

by David P Sauter

Computational and Information Sciences Directorate, ARL

Approved for public release; distribution unlimited.

FOR OFFICIAL USE ONLY (delete if not FOUO)
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11 Aug 2014–23 Aug 2014 

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Wet-Bulb–Globe Temperature Data Report 

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David P Sauter 

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US Army Research Laboratory 

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White Sands Missile Range, NM 88002-5501 

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ARL-SR-0317

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Approved for public release; distribution unlimited. 

13. SUPPLEMENTARY NOTES

14. ABSTRACT

The Wet-Bulb–Globe Temperature (WBGT) is used extensively by the US military (and others) to provide guidance for work 

and rest periods as well as water intake by Soldiers in a hot environment. In an effort to help validate a predictive WBGT 

algorithm in use in a heat-stress-guidance application, WBGT data measurements were performed at Eglin Air Force Base, 

Florida, in August 2014. The data and a brief data analysis are included in this report. 

15. SUBJECT TERMS

Wet-Bulb–Globe Temperature, heat stress 

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20 

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David P Sauter 

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(575) 678-2078 

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iii 

Contents

List of Figures iv

List of Tables iv

Acknowledgments v

1. Introduction 1

2. Instrumentation and Site Overview 1

3. Data Analysis 3

4. Data 4

5. References 10

Distribution List 11
iv 

List of Figures

Fig. 1 3M QUESTemp° 32 Sensor .........................................................................1

Fig. 2 Sigma Products tactical WBGT kit ..............................................................2

Fig. 3 Kestrel 4400 Heat Stress Tracker .................................................................2

Fig. 4 Eglin AFB’s WBGT data-collection site ......................................................3

List of Tables

Table 1a WBGT and Meteorological Data for Quest, Sigma 1 (S1), and Kestrel 2 

(K2) Sensors..............................................................................................5

Table 1b WBGT and Meteorological Data for Quest, Sigma 1 (S1), and Kestrel 2 

(K2) Sensors..............................................................................................6

Table 1c WBGT and Meteorological Data for Quest, Sigma 1 (S1), and Kestrel 2 

(K2) Sensors..............................................................................................7

Table 2a WBGT and Meteorological Data for Quest, Sigma 2 (S2), and Kestrel 1 

(K1) Sensors..............................................................................................8

Table 2b WBGT and Meteorological Data for Quest, Sigma 2(S2), and Kestrel 1 

(K1) Sensors..............................................................................................9
v 

Acknowledgments

The author would like to acknowledge the 96th Weather Flight at Eglin Air Force 

Base, Florida, for its outstanding support before, during, and after the datacollection effort. Special thanks go to Mr. David Biggar, staff meteorologist with 

the 96th. 

 
vi 

INTENTIONALLY LEFT BLANK. 
1 

1. Introduction  

The Wet-Bulb–Globe Temperature (WBGT) is used extensively by the US military 

(and others) to provide guidance for work and rest periods as well as water intake 

by Soldiers in a hot environment. In an effort to validate a predictive WBGT 

algorithm within a heat-stress-guidance application, WBGT-data measurements 

were performed at Eglin Air Force Base (AFB), Florida, in August 2014. A recent 

paper (Sauter 2013) provides details of the heat-stress-guidance application and the 

role of the WBGT. This report includes an overview of the instrumentation and site, 

the actual data, and a brief analysis of the data. The primary intent is to make the 

data available (an Excel spreadsheet of the data is available upon request). 

2. Instrumentation and Site Overview

The WBGT consists of 3 separate temperature components (Sauter 2013): 

 Ambient dry-bulb temperature (Td) 

 Natural wet-bulb temperature (Tw) 

 Black-globe temperature (Tg) 

These values are typically measured directly as with the 3M QUESTemp° QT32 

sensor (Fig. 1) or the Sigma Products tactical WBGT kit (Fig. 2). 

Fig. 1 3M QUESTemp° 32 Sensor 
2 

Fig. 2 Sigma Products tactical WBGT kit 

In the case of the Kestrel 4400 Heat Stress Tracker (Fig. 3), the natural wet-bulb 

component of the WBGT is computed as a function of the measured ambient 

temperature and humidity values. 

Fig. 3 Kestrel 4400 Heat Stress Tracker 

One each of the QT32, Sigma, and Kestrel sensors was used simultaneously in the 

data-collection process. Two each of the Sigma Products kits and the Kestrel 4400 

meters were available and were interchanged approximately halfway through the 

data-collection period. 
3 

Data collection was conducted at Eglin AFB in a grassy and somewhat open area 

(Fig. 4). August was chosen in order to collect data in a hot and humid environment 

that lends itself to relatively high WBGT values and conditions favorable for heatstress injuries. As the QT32 instrument is not designed to be exposed to 

precipitation, there are no observations for rainy conditions. Readings were 

generally taken every 30 min between mid-morning and late afternoon. A sampling 

duration of 60 s was chosen. The Kestrel 4400 sensor is able to automatically take 

samples every 2 s over the minute period and then display the average WBGT 

component values. For the Sigma WBGT kit and the QT32 sensor, the readings 

were taken immediately after the Kestrel readings were initiated and then again 

immediately after they were concluded. These values were then simply summed 

and halved to provide the average. 

Fig. 4 Eglin AFB’s WBGT data-collection site 

3. Data Analysis

Although not intended to be a complete and detailed analysis of the data, the 

following observations have been made regarding the measurements from the 

various instruments, some of which belonged to the US Army Research Laboratory 

(ARL) and some to the 96th Weather Flight. 

1) Compared to the QT32 and Sigma instruments, the Kestrel 4400 Heat Stress 

Meter’s derived Tw values are too high (4–6 °F or more) under conditions 

with significant, direct solar load on the instrument. The Nielsen–Kellerman 

Co. (manufacturer of the Kestrels) was contacted regarding this bias (Sauter 
4 

2014a) and modifications to the software that computes the Tw were made. 

Subsequent measurements will be made once the updated sensor is 

received. 

2) Under conditions of high solar load and light wind speeds, the Sigma 

Products Td values typically exhibited an 8–10 °F warm bias as compared 

to the QT32 and Kestrel devices (as well as to a National Weather Service 

measuring site located less than a mile away). This information was 

provided to a Sigma Products representative (Sauter 2014b). As a result, the 

author was provided 2 additional tactical WBGT kits that were painted 

white (one matte and the other glossy) instead of the dark green of the 

original sensor. Limited follow-on measurements with the white sensors 

indicated somewhat lower Td readings, but still higher than expected. 

Additional observations are anticipated later in 2015. 

3) Although the relative-humidity (RH) value is not used by the QT32 sensor 

in the computation of the WBGT, the value exhibits a significantly low bias 

(20% or more) under hot and sunny conditions. It is believed that this is due 

to the RH sensor being located inside the QT32 housing and not being 

adequately ventilated. This was reported to a 3M (manufacturer of the 

QUESTemp sensors) representative (Sauter 2014c) who concurred with the 

finding. 

While at Eglin AFB, several readings from a second QT32 sensor (property of the 

96th Weather Flight) were compared to the ARL’s QT32 and provided nearly 

identical results. The QT32 sensor readings are considered the baseline values. 

4. Data

The raw data from the Eglin AFB site are included in the following tables. Tables 

1a–1c include the observations for Sigma sensor 1 and Kestrel sensor 2 while 

Tables 2a–2b include Sigma sensor-2 and Kestrel sensor-1 observations. An Excel 

spreadsheet of the data is available from the author upon request. 
5 

Table 1a WBGT and Meteorological Data for Quest, Sigma 1 (S1), and Kestrel 2 (K2) Sensors 

Notes: All observations were taken at 30.49° N, 86.52° W (Eglin AFB). Local time = GMT – 5 h. a 0 = none; 1 = stratocumulus; 2 = cumulus; 3 = altostratus/altocumulus; 5 = thin cirrus; 6 = thick cirrus; 7 = precipitation. b 0 = sun not obscured; 1 = sun partially obscured; 2 = sun obscured. c National Weather Service observation site at the Northwest Florida Regional Airport (Valparaiso), less than 1 mile south–southwest of the WBGT obs

SIGMA 1 QUEST KESTREL 2

Mon Day Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBG

GMT millibars deg F deg F deg F deg F deg F deg F deg F deg F deg F mph tenths codea codeb % % % deg F 

8 11 16 22 1013.2 94.5 80 110 88.7 80.6 111.5 87.8 86.4 111 3.5 3 2 0 51 73 87.5 8 11 16 56 1012.7 93.5 81.5 113.5 90 81.2 111.1 90 84.7 108.9 1.8 3 2 0 48 63 62 89.1 8 11 17 36 1012.8 94.5 80.5 110.5 91 80.8 112.4 90.1 83.7 113.2 2.3 3 2 2 41 58 87.9 8 11 18 15 1012.5 93 80.5 112.5 90.1 80.7 109.2 89.1 82 106.9 3.4 5 2 0 46 60 56 88.2 8 11 18 55 1012.1 91 80 101 88.7 81.2 101.5 88.9 83.3 100.9 1.8 5 2 2 51 68 68 85.3 8 11 20 0 1011.2 96.5 81.5 126 93 81.3 117.3 92.5 84.6 113 4.3 2 2 0 42 53 54 91.9 8 11 20 30 1011 95.5 81 114 92.3 81 107 92.3 82 104.7 3.2 3 2 0 42 54 89.1 8 11 21 0 1011 95 79.5 106.5 92.3 80.7 105.4 92.8 80.8 102.7 1.7 4 2 1 40 51 51 86.5 8 11 21 30 1011 93 78 106 91.4 79.9 101.4 91.9 81.7 103.3 1.4 4 2 2 42 55 85.1 8 12 14 20 1012.1 86 79 101.5 83.6 78.8 103.8 91.8 81.1 96.6 0.3 5 4 1 60 61 84.2 8 12 15 0 1011.9 89.5 80 112 86.5 80.1 110.4 92.1 85.8 104.4 0.5 5 4 1 41 62 74 87.4 8 12 15 30 1012.2 93 81.5 119.5 88.6 81.3 117.7 89.1 86 113.9 1.2 6 4 1 38 64 90.3 8 12 16 0 1011.9 95 80.5 118.5 89.6 81.3 117.2 89.1 86.4 118.2 2.2 7 4 1 35 64 70 89.6 8 12 16 30 1011.6 89 79 100 86.1 79.7 100.5 86.4 82.8 99.3 1.1 8 5 1 53 72 84.2 8 12 17 0 1012 88.5 79 101 86.2 79.6 101.1 86.4 82.2 99.3 1.2 9 5 2 53 71 70 84.4 8 12 17 30 1011.9 91 80.5 105.5 87.2 80.5 105.6 87.4 83.8 103.8 2 9 5 1 52 70 86.6 8 12 18 0 1011.8 93.5 80 115 89.5 80.5 113.4 89.1 85.1 113 2 8 5 1 43 64 64 88.4 8 12 18 30 1011.7 93 79.5 106.5 88.4 80.1 107.4 89.8 84 107.8 2 8 3 1 47 62 86.3 8 12 19 0 1011.1 96.5 80.5 117.8 90.9 80.6 117.6 91.2 85.8 116.1 2.7 5 5 0 42 59 62 89.6 8 12 19 30 1010.8 96.3 80 116 91 81 116.8 92.1 84.6 114.4 2.8 4 5 0 42 56 88.8 8 12 20 0 1010.2 95.3 80 113.8 90.7 80.8 113 91 84 111.6 2.7 5 5 0 42 58 59 88.3 8 12 20 30 1010.2 93.5 79 110.5 90.1 80.4 111.4 90.9 84.6 111.9 2 7 5 1 40 59 86.8 8 12 21 0 1010.5 94.3 80.8 113 90.5 81.3 114 91.8 85.5 113.2 2.7 6 5 0 43 59 62 88.6 8 13 14 30 1012.8 82.3 76.3 89.5 81.2 77.1 89.7 82.4 76.8 87.6 0.7 6 5 2 71 76 79.5 8 13 15 0 1012.9 86 78 108.3 84.2 79.1 110.5 82.8 82.9 108.9 2.1 5 5 1 49 75 79 84.9 8 13 15 30 1012.8 92 82 123 88.6 81.5 119.1 88.9 85.5 111.4 0.5 4 5 0 38 64 91.2 8 13 16 0 1012.7 96 80.5 121.5 90 81.5 121.8 91.4 83.8 113.2 0.1 3 5 0 39 53 66 90.3 8 13 16 30 1012.8 97.8 84.5 125.5 93.1 84.1 123.1 94.1 89.2 121.5 1.6 3 2 0 38 59 94.0 8 13 17 0 1012.7 99.5 84.8 125 93.6 84.1 122.4 94.5 88.5 115.9 2.4 3 2 0 39 58 66 94.3 8 13 17 30 1012.4 96.5 82.8 118.5 92.5 82.5 115.4 92.3 86.5 114.6 1.9 3 2 0 40 61 91.3 8 13 18 0 1012.3 97.3 83.8 117 92.3 83.4 115.6 91.9 86.4 113.7 2.2 3 2 0 44 61 66 91.8 8 13 18 30 1012 97 82.8 118.8 92.8 82.7 116.9 93.2 87.1 116.4 2.5 3 2 0 43 59 91.4 8 13 19 7 1011.3 98 82.8 115.3 92.9 82.9 116.2 92.5 86.4 116.4 2.8 3 2 0 44 59 66 90.8 8 13 19 30 1011.4 98 82.3 115.3 93.3 82.8 117.9 94.6 87.4 117.7 2.5 3 2 0 41 56 90.5 8 13 20 0 1011.1 95 81.5 108.8 91.6 82 109.7 92.1 84.7 110.3 2.9 3 2 1 46 59 66 88.3 8 13 20 30 1010.7 96.5 82.5 114.8 92.3 82.8 115.5 93.2 85.3 107.2 1.8 2 2 0 46 59 90.4 
6 

Table 1b WBGT and Meteorological Data for Quest, Sigma 1 (S1), and Kestrel 2 (K2) Sensors 

Notes: All observations were taken at 30.49° N, 86.52° W (Eglin AFB). Local time = GMT – 5 h. 

a 0 = none; 1 = stratocumulus; 2 = cumulus; 3 = altostratus/altocumulus; 5 = thin cirrus; 6 = thick cirrus; 7 = precipitation. b 0 = sun not obscured; 1 = sun partially obscured; 2 = sun obscured. c National Weather Service observation site at the Northwest Florida Regional Airport (Valparaiso), less than 1 mile south–southwest of the WBGT observation 

SIGMA 1 QUEST KESTREL 2

Mon Day Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT 

GMT millibars deg F deg F deg F deg F deg F deg F deg F deg F deg F mph tenths codea codeb % % % deg F 

8 13 21 0 1010.8 90.8 79.8 101 89.8 80.8 100.7 89.6 84 106.3 2.7 4 2 2 49 65 62 85.1 8 13 21 30 1010.7 94.3 80.5 111.5 91.6 81.4 112.5 92.3 85.5 113.4 3.3 3 2 0 44 58 88.1 8 14 14 0 1014.1 85 72.8 103.8 84 73.2 104 83.1 76.3 104.9 2.9 2 5 0 39 55 55 80.2 8 14 14 30 1014.2 88.5 73.5 106.5 85.6 74.6 107.9 86.2 77.9 107.4 2.8 2 5 0 35 50 81.6 8 14 15 0 1014.2 89.5 73.8 108 86.8 74.6 107.8 86.7 78.6 108.7 2.4 3 5 0 34 51 52 82.2 8 14 15 30 1014.3 93.3 74.8 113.5 89 75.6 113.9 88.3 79.9 113.7 2.1 3 5 0 31 48 84.4 8 14 16 0 1014.4 94.8 77 116.5 91.2 77.7 116.2 93 79.9 109.9 0.7 5 4 1 32 42 52 86.7 8 14 16 30 1014.1 92 76.3 106.5 89.1 76.5 109.1 88 80.4 112.6 5.8 7 5 1 37 52 83.9 8 14 17 0 1013.7 94.5 77.8 111.3 90.3 77.9 113.2 90 81.5 111.7 2.7 8 4 1 37 51 55 86.2 8 14 17 30 1013.3 96.3 79.3 118 92.5 79.5 117.3 93.2 84.4 115.7 2.2 7 4 1 37 50 88.7 8 14 18 0 1012.8 99.3 80.3 126 93.4 80.1 124.4 92.7 84 118.8 3.5 4 4 0 34 48 54 91.3 8 14 18 30 1012.6 97 79.3 112.3 92 79.8 112.9 91.6 82.9 113.2 2.5 4 2 1 38 53 87.7 8 14 19 0 1012.3 94 77.5 110.5 91.3 78.8 109.1 89.8 82 113 3.1 4 2 1 39 54 57 85.8 8 14 19 30 1011.7 99.8 81.3 118.8 94 81.9 121.1 93.7 86.4 120.2 2.3 3 2 0 38 53 90.7 8 14 20 0 1011.7 100.8 80.8 122.8 94.7 81.5 123.4 95 86 121.6 2 3 2 0 33 49 56 91.2 8 14 20 30 1011 99 79.8 119 94.4 81 119.2 94.8 84 115.3 1.4 4 2 0 34 48 89.6 8 14 21 0 1011.3 96 78.8 115.5 92.9 79.9 116.2 92.7 82.8 114.8 2.2 4 2 0 34 49 56 87.9 8 14 21 30 1011.2 96 80 114.5 93.2 80.9 115 92.5 83.7 113.9 2.5 3 2 0 37 53 88.5 8 14 22 0 1011.2 93.5 78.3 110.3 91.4 79.5 111.3 89.6 82.2 113.2 4 3 2 0 39 55 56 86.2 8 14 22 30 1011.1 91 78.5 107.5 90.3 79.6 107.2 91 82.4 107.1 1.8 2 3 0 43 56 85.6 8 15 14 0 1014.1 88.8 73.5 105 84.2 74.1 105.1 83.8 77.7 103.6 1.9 4 4 1 45 57 51 81.3 8 15 14 30 1014.3 93 74 112 86.8 75.2 113.9 87.4 79.7 111.6 2.2 5 4 0 34 50 83.5 8 15 15 0 1014.3 93.5 75.8 116.5 88.5 77 117.4 91.4 80.1 108.7 0.2 4 5 1 31 42 49 85.7 8 15 15 30 1014.3 94.3 74.5 115.5 88.7 75.5 115.3 87.8 78.4 114.8 3.2 5 5 0 33 45 84.7 8 15 16 0 1014.2 93 74.8 114.5 89 75.8 112.1 88.9 78.6 109.4 1.8 5 5 1 35 47 44 84.6 8 15 16 30 1013.8 94 76 116 90.4 76.7 116.9 89.2 80.2 114.3 3.2 4 5 0 33 47 85.8 8 15 17 0 1013.3 94.3 76 114.3 91.1 76.9 115.4 89.6 80.2 117.5 3.9 4 5 0 34 46 43 85.5 8 15 18 0 1012.8 94 75.8 107 91.1 77.4 106.5 90.5 78.8 104.4 2 4 2 2 36 49 48 83.9 8 15 18 30 1012.5 100 79.3 120 94.6 79.7 120.4 94.8 84.9 122.7 2.6 3 2 0 33 45 89.5 8 15 19 0 1012.5 100 78.8 120 94.8 79.5 122.1 94.3 84 123.4 3 4 2 0 31 44 49 89.2 8 15 19 30 1012.5 94.8 76.8 107 91.8 77.7 108.6 92.5 81 111.4 3 3 2 1 36 46 84.6 8 15 20 0 1012.3 95.3 77.5 111 92.1 78.2 111.9 91.8 81.9 113.7 4.1 2 2 0 36 49 51 86.0 8 15 20 30 1012.2 94.5 76.8 110 91.4 78 110.7 91.6 80.8 110.8 3.6 2 4 0 37 48 85.2 8 15 21 0 1012.1 94.8 77.5 112 91.6 78.6 112.3 91.8 82.2 113.2 3.7 3 4 0 38 50 51 86.1 8 15 21 30 1012.1 93.3 77.5 110.5 91.1 78.9 111.4 91.4 81.9 110.7 2.9 3 4 0 38 51 85.7 8 15 22 0 1012 90.5 76 105.3 89.5 77.3 106.5 89.2 79.7 107.4 3.5 4 4 1 40 52 52 83.3 
7 

Table 1c WBGT and Meteorological Data for Quest, Sigma 1 (S1), and Kestrel 2 (K2) Sensors 

Notes: All observations were taken at 30.49° N, 86.52° W (Eglin AFB). Local time = GMT – 5 h. a 0 = none; 1 = stratocumulus; 2 = cumulus; 3 = altostratus/altocumulus; 5 = thin cirrus; 6 = thick cirrus; 7 = precipitation. b 0 = sun not obscured; 1 = sun partially obscured; 2 = sun obscured. c National Weather Service observation site at the Northwest Florida Regional Airport (Valparaiso), less than 1 mile south–southwest of the WBGT observati

SIGMA 1 QUEST KESTREL 2

Mon Day Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 

GMT millibars deg F deg F deg F deg F deg F deg F deg F deg F deg F mph tenths codea codeb % % % d

8 15 22 30 1011.9 90 75.8 104.5 89.5 77 105.6 88 79.2 106.5 5.4 3 4 1 42 53 8 16 15 30 1015.4 95.8 78.5 123.3 93.1 79.2 120.4 99.3 84.9 115.7 1.3 2 2 0 31 40 8 16 16 0 1015.3 96.5 78.3 117.3 92.6 79.5 119.6 93.4 84.2 122.2 2.2 4 2 0 33 44 8 16 16 35 1015.3 99 81.5 122.3 94.9 81.6 122.3 95.4 85.8 120.7 2.2 5 2 0 30 47 8 16 17 0 1015.3 94.8 80.3 111.3 92.2 81 110.1 92.3 82.9 108.3 2.4 6 2 1 39 54 59 8 16 17 30 1014.9 90.3 78.5 103.3 90.3 79.7 101.5 89.2 82.6 109 2.6 6 2 2 40 60 8 16 18 0 1014.8 95.8 81.8 116 93.2 81.5 114.5 92.8 84.9 113.5 3.8 6 2 1 40 56 59 8 16 18 30 1014.6 96.5 81 109.3 92.7 81.4 112.1 93.2 84.2 108.7 3.2 6 2 2 46 54 8 16 19 0 1014.6 98.5 81.3 113.8 93.8 81.7 116.4 93.7 86.2 115.3 3.3 6 2 1 40 54 56 8 16 19 30 1014.2 97.3 79.5 110 93.6 80.7 113.7 93.7 84 112.3 3.6 6 2 1 39 52 8 16 20 0 1013.9 99.3 82.3 113 94.7 83.2 116.1 94.8 86.2 114.8 4 6 2 0 41 53 56 8 16 20 30 1013.7 97 81.3 114 93.8 82.2 115.9 93.9 86.4 118 4.2 5 2 0 40 55 8 18 14 0 1014.3 87.5 80.8 109 86.6 81.5 108.9 90.1 86.4 108.1 2.3 3 2 0 51 69 78 8 18 14 30 1014.5 89.5 80.3 109 88.4 81.5 106.4 88.2 85.1 106.5 2 5 2 1 46 71 8 18 15 0 1014.8 92.8 82 119.5 90.9 82.1 116.9 90.7 85.5 111.9 2.6 5 2 0 38 62 68 8 18 15 30 1014.6 93 80.8 110.5 91 81.1 109.9 92.7 84 107.8 2.1 6 2 1 38 57 8 18 16 0 1014.3 92.3 81 117.5 91.8 81.6 111.3 92.5 85.5 109.9 1.8 8 2 1 37 59 66 8 18 16 30 1014.2 89 81.3 105 89.3 81.5 98.8 88.2 85.1 108.3 4.4 8 2 2 48 70 8 18 17 0 1013.8 93.3 82.5 116.5 91.8 82.1 110.9 90.3 84.9 110.1 6.8 8 2 1 47 62 66 8 18 17 30 1013.6 93.3 82 117.3 91.6 81.5 110.3 90.5 84.7 111.6 5.1 8 2 1 44 61 8 18 19 30 1012.8 80 76 86.5 79 76.4 88 79.9 77.2 82.2 0.5 9 3 2 78 84 8 18 20 0 1012.4 84.8 78.5 94 82.2 78.9 95.6 83.7 82.2 91.9 0.2 9 3 2 70 81 84 8 18 20 30 1012.2 87 80.5 96.8 84.6 81 98.1 86.5 83.1 95.2 0.9 9 3 2 69 77 8 18 21 0 1012.4 89.5 81.5 99.5 86.3 82.3 101.5 88.3 84.9 98.1 0.5 9 3 2 65 75 79 8 19 14 0 1013.9 85 80 90 84.7 80.6 90.5 84.4 79.9 90.3 1.4 7 2 2 71 81 78 8 19 14 30 1013.7 89.3 81.8 103 87 82.1 106.5 89.2 86.9 104 3.1 5 2 0 62 74 8 19 15 0 1013.8 90.3 81.3 112 89.3 82 111.5 89.4 86.9 111 3.4 4 2 0 44 70 70 8 19 15 30 1013.9 91.5 80.8 108.8 89.7 81.5 111.1 88.9 84.4 106.9 5.9 5 2 1 46 67 8 19 16 0 1013.6 93.8 81.5 114 91.2 81.9 114.3 90 86.7 119.5 3.6 5 2 0 40 63 64 8 19 17 35 1013.1 92.8 85.3 128 90 84.1 120.2 88.7 88.7 112.6 3.4 6 2 0 50 75 8 19 18 0 1012.7 90.8 80.3 109.3 89.8 80.6 104.2 89.1 83.1 103.5 3.6 8 2 1 46 66 62 8 19 18 30 1012.5 93.8 81.8 106.3 90.8 81.9 109.9 90.1 85.8 112.1 7.2 5 2 0 48 65 8 19 19 0 1012.3 94.3 80.5 105.5 91.3 80.5 108.6 90.7 83.8 112.3 6.3 4 2 0 44 58 56 8 19 19 30 1011.9 94 81 108.3 91.5 81.4 110.7 91 85.3 112.5 5.3 3 2 0 45 61 8 19 20 0 1011.7 94.3 80.8 107 91.5 81.1 110.2 91.6 84 110.7 4.2 4 2 0 43 57 57 8 19 20 30 1011.6 92.3 80 102.8 90.3 80.8 106.1 90.1 84.4 108.3 6.8 3 2 0 48 63 8 19 21 0 1011.5 92 79.3 103 90.4 80 105.9 90.1 82.8 107.1 5.8 3 5 0 47 59 60 8 19 21 30 1011.4 92.8 79.8 104 91 80.6 107.5 91 83.5 109.2 5.9 3 5 0 47 58 8 19 22 0 1011.3 90.3 79.5 100.3 89.6 80.3 103.1 89.2 82.2 103.8 5.9 3 5 0 51 62 63 
8 

Table 2a WBGT and Meteorological Data for Quest, Sigma 2 (S2), and Kestrel 1 (K1) Sensors 

Notes: All observations were taken at 30.49° N, 86.52° W (Eglin AFB). Local time = GMT – 5 h. 

a 0 = none; 1 = stratocumulus; 2 = cumulus; 3 = altostratus/altocumulus; 5 = thin cirrus; 6 = thick cirrus; 7 = precipitation. b 0 = sun not obscured; 1 = sun partially obscured; 2 = sun obscured. c National Weather Service observation site at the Northwest Florida Regional Airport (Valparaiso), less than 1 mile south–southwest of the WBGT o

SIGMA 2 QUEST KESTREL 1

Mon Day Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S2 WBGT 

GMT millibars deg F deg F deg F deg F deg F deg F deg F deg F deg F mph tenths codea codeb % % % deg F 

8 20 14 0 1015.7 87.3 79.8 104.8 86 80.6 105.7 86.9 88.2 105.3 2.7 1 5 0 54 86 74 85.6 8 20 14 30 1016 90 81.3 110.8 88.7 81.9 111.3 87.8 89.2 112.1 3.6 2 2 0 45 82 88.1 8 20 15 0 1016.2 93 82.8 114.3 90.3 83 115.1 92.1 90.9 109.8 1.5 4 2 1 44 75 68 90.1 8 20 15 30 1016.2 95.5 83 120 92.6 83.6 120 92.1 90.7 118.8 3.4 4 2 0 39 71 91.7 8 20 16 0 1016.5 91 79.8 102 88.8 81.1 103.6 88.3 84.4 102.6 2.6 4 2 1 53 73 59 85.4 8 20 16 30 1016.3 98.5 84 122.3 94.3 83.4 121.5 96.4 91.2 118.2 1.3 5 2 0 40 61 93.1 8 20 17 0 1015.9 99 83.3 119.3 94.6 82.3 118.3 92.7 85.6 110.7 2.8 5 2 0 36 59 64 92.1 8 20 17 30 1015.7 100.5 86.8 128.5 95.9 85.2 123.7 93.6 92.3 125.2 3.7 7 2 0 40 68 96.5 8 20 18 0 1015.7 93.5 79.8 109 92.2 80.7 109.5 90.5 85.3 111.9 3.5 8 2 2 42 63 67 87.0 8 20 21 50 1014.9 76 72.5 76 75 72.7 76.1 75.2 72.5 76.1 0.6 9 3 2 89 87 87 73.6 8 20 22 15 1014.8 75.5 73.5 76 74.7 73.7 76.2 75 73.8 75.9 0 9 3 2 95 95 74.2 8 21 14 0 1018.4 86.3 80.8 103.3 85 81.3 102.8 83.8 86.4 103.8 5.3 2 4 0 67 91 81 85.9 8 21 14 30 1018.2 91.3 81.8 108.5 86.9 82.2 106.8 85.6 87.8 107.1 4 2 4 0 62 87 88.1 8 21 15 0 1018.2 94 82 110 87.9 82.1 108.7 86.7 87.4 109 4.4 1 4 0 59 81 73 88.8 8 21 15 30 1018.2 94 81.3 114 89.5 81.8 112.8 87.8 87.4 112.3 5.3 1 2 0 51 75 89.1 8 21 16 0 1018.1 96.5 82.3 117 90.9 82.6 116.5 89.4 89.8 117.5 2.9 2 2 0 46 75 63 90.7 8 21 16 30 1017.7 100.3 83 127.8 94 83.6 125.9 92.7 91.6 122.5 1.6 3 2 0 37 67 93.7 8 21 17 0 1017.5 104.5 83.5 121.3 94 83.9 125.6 93.6 89.2 115.5 1.3 4 2 0 42 62 59 93.2 8 21 17 30 1017.4 101.3 87 122.3 95.9 86.5 123.5 94.3 91.6 117.3 2.4 4 2 0 43 69 95.5 8 21 18 0 1017.2 101.5 86 121.5 94.5 85.8 120.9 93.4 92.8 121.3 2.7 3 2 0 46 72 68 94.7 8 21 18 30 1017.2 101.5 86.3 120.8 94.8 86.1 120.6 93.9 92.8 119.5 2.3 3 2 0 46 73 94.7 8 21 19 0 1016.7 102.5 86.5 121.8 95.4 86.3 122.7 94.5 93 122.2 2.2 4 2 0 44 71 68 95.2 8 21 20 10 1015.6 98 83.8 113.3 93.7 84.8 114 93 91.4 117.1 2.5 5 2 0 44 73 91.1 8 21 21 0 1015.2 93.3 81 105 89.8 81.6 106 89.2 85.8 102.6 1.6 5 2 1 49 74 65 87.0 8 21 21 30 1015.2 96 82.3 111.8 92.1 82.8 113.5 91.2 88.9 112.6 2.5 5 2 0 43 72 89.6 8 21 22 0 1015.3 97 82.3 113.8 93.1 83.4 115.8 91.4 88 115.7 2.6 4 2 0 42 67 64 90.1 8 21 22 25 1015.3 95.8 82 109.8 92.4 83.1 112.3 91 87.8 112.1 2.6 5 4 1 44 71 88.9 8 22 14 0 1016.5 90 79.8 106.5 87.4 81 106.3 86.4 85.3 106.3 3.2 0 0 0 57 77 67 86.2 8 22 14 30 1016.6 92 80.5 108.3 88.4 81.3 107.9 87.3 86.5 109.6 4.8 0 0 0 54 76 87.2 8 22 15 35 1016.7 98.8 82 116.3 92.7 82.8 114.1 91.4 87.1 113.5 3.4 0 0 0 46 64 90.5 8 22 16 0 1016.7 98 81.5 117.5 93.4 82.4 116.5 91.8 87.3 117.9 4.4 0 0 0 43 62 55 90.4 8 22 16 30 1016.5 100 81 117.3 93.9 81.8 113.7 93.2 87.6 117.3 5.6 4 2 0 45 60 90.2 8 22 17 0 1016.1 99 81.8 119.8 95.3 82.7 120.2 93.9 88.3 121.6 3.8 6 2 0 35 58 49 91.1 8 22 17 30 1015.9 94.8 79 107 93.4 80.5 104.9 92.7 83.3 106.3 2 8 2 2 39 57 86.2 8 22 18 0 1015.5 104.3 83 135.5 99.3 83.4 131.5 97.2 90.5 133.7 2.5 8 2 0 28 50 95.6 8 22 18 30 1015.4 96.8 79.8 102.3 94.1 81.1 103.6 94.8 83.1 101.1 0 9 2 2 40 53 86.0 8 22 19 0 1014.7 93 80.5 97.8 91.9 81.7 98.4 91.2 83.1 100 2.8 8 2 2 50 65 85.2 8 22 19 30 1014.4 96.3 82 105.5 93.9 83.1 105.7 93 87.4 109.9 2 9 2 2 44 66 88.1 
9 

Table 2b WBGT and Meteorological Data for Quest, Sigma 2(S2), and Kestrel 1 (K1) Sensors 

Notes: All observations were taken at 30.49° N, 86.52° W (Eglin AFB). Local time = GMT – 5 h. a 0 = none; 1 = stratocumulus; 2 = cumulus; 3 = altostratus/altocumulus; 5 = thin cirrus; 6 = thick cirrus; 7 = precipitation. b 0 = sun not obscured; 1 = sun partially obscured; 2 = sun obscured. 

c National Weather Service observation site at the Northwest Florida Regional Airport (Valparaiso), less than 1 mile south–southwest of the WBGT o

SIGMA 2 QUEST KESTREL 1

Mon Day Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S2 WBGT Q 

GMT millibars deg F deg F deg F deg F deg F deg F deg F deg F deg F mph tenths codea codeb % % % deg F 

8 22 20 0 1013.9 100.5 82.5 116 96.4 83.3 116.9 94.8 89.1 120.2 3.4 8 2 1 38 60 91.0 8 22 20 30 1013.5 102.5 82.5 119.3 97.6 83.6 121.8 95.5 88.5 121.6 4.1 7 2 0 35 56 91.9 8 22 21 0 1013.6 102 82.5 118.8 97.7 84 120.8 96.6 88.3 119.1 2.6 6 2 0 34 56 91.7 8 22 21 30 1013.4 99 82.5 114.8 96 83.8 116.6 96.4 90.1 117 2 7 2 0 40 61 90.6 8 22 22 0 1013.3 95 83.3 107.8 93.3 84 109.8 92.3 88.7 109.2 4.6 6 2 0 51 72 89.4 8 23 14 35 1013.6 95.8 82 112.5 91.7 82.3 111.8 90.1 86.5 110.5 2.9 2 5 0 53 68 89.5 8 23 15 0 1013.5 97 81.3 113.3 92.4 82.2 111.9 90.5 85.6 111 5.2 2 5 0 49 64 57 89.3 8 23 15 30 1013.5 98 80.8 116 93.9 82.1 114.7 92.1 86.4 115.5 5.6 2 5 0 43 60 89.6 8 23 16 30 1013.2 96.2 81.3 122.8 94.5 87.4 124.3 4.7 4 2 0 34 53 8 23 16 55 1012.9 97.1 82.2 124.1 95.4 87.6 124.7 5 5 2 0 36 52 45 8 23 17 25 1012.6 98.2 82.6 127.5 98.4 88 121.6 1.1 6 2 0 32 46 8 23 17 55 1012.1 99.1 81.8 130.5 95.9 87.1 128.1 2.6 6 2 0 30 47 43 8 23 18 20 1011.9 99.1 81.6 128 97 88 128.7 4.9 7 2 0 29 47 
10 

5. References

Sauter DP. A wet-bulb globe temperature validation study using standard 

meteorological inputs and modeled solar irradiance. J Oper Meteor. 

2013:1(18):215–225. 

Sauter D. Personal communication (Joe Racosky, Advanced Technical and 

Customer Support Engineering, the Nielsen–Kellerman Co.), 2014a. 

Sauter D. Personal communication (Matt Cramer, General Manager, Sigma 

Products), 2014b. 

Sauter D. Personal communication (Mark E. Scherer, Technical Support Engineer, 

Detection Portfolio 3M Personal Safety Division, Quest Technologies), 2014c. 
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