The Kestrel 5400 Heat Stress Tracker was designed to help prevent human heat stress for those who work or train outdoors.  The Kestrel 5400 uses a 1 inch black globe to gather important environmental details that relate to human heat stress.

Available on back-order


The Kestrel 5400 Heat Stress Tracker was designed to help prevent human heat stress for those who work or train outdoors.  The Kestrel 5400 uses a 1 inch black globe to gather important environmental details that relate to human heat stress.  It measures Wet Bulb Globe Temperature (WBGT) and Thermal Work Limit (TWL)

The closest competitor in quality and accuracy in the heat stress market is the Quest, which costs about twice as much, nearly 10X the weight and size.  The Kestrel Heat Stress meters are revolutionizing an industry.
While the details of how the WBGT and TWL are calculated are proprietary to the US manufacturer at NK, here is what we can offer from the specification chart:

Outdoor Wet Bulb Globe Temperature (WBGT)

Measure of human heat stress defined as the combination of effects due to radiation, convection, and conduction. Outdoor WBGT is calculated from a weighted sum of natural wet bulb (Tnwb), globe temperature (Tg), and dry bulb temperature (Td). User settable on-screen warning zones.

Thermal Work Limit  (TWL)

Estimated safe maximum continuously sustainable human metabolic rate (W/m2) for the conditions and clothing factors. Based off of estimated metabolic output of typical human. On-screen zone warnings.

The portable meter allows users to create customized warning zones and alarms depending on their current work environment and also has the functionality to store different profiles.  It’s the perfect solution for those who have several different work sites, or who follow different standards depending on where they are training. Kestrel Wind Meters are used by NFL trainers to determine how frequently the athletes need to hydrate, and when the conditions are unhealthy for strenuous exercise.

5400 Features:

  • Thermal Work Limit (TWL)
  • Wet Bulb Globe Temperature (WBGT)
  • Naturally aspirated Wet Bulb Temperature
  • Wind speed
  • Max wind gust
  • Average wind speed
  • Temperature
  • Wind chill
  • Relative humidity
  • Heat stress index
  • Dew point temperature
  • Wet bulb temperature
  • Barometric pressure
  • Altitude
  • Density altitude
  • Pressure trend

The Kestrel 4000 is waterproof, able to float and includes an easy to read backlit display that shows the minimum, maximum and average values for every measure.  The automatic or manual data logging features makes it easy to store, recall, and graph data sets and customizable user screens allow users to group key measurements.  Data can be easily uploaded to a computer with an optional interface, allowing for easy storage and analysis of data for later use.

In addition to being easy to use, the Kestrel 5400 was also designed to be highly durable in the field.  The Kestrel 5400 features external temperature and humidity sensors for fast and accurate readings, and a patented “no-tools replaceable” wide-range air flow impeller that instantly restores the meter back to it’s factory calibration.  The meter was designed with a flip-top impeller cover that allows for the use of other functions while protecting the impeller.  The meter was built with a highly stable humidity sensor that rarely requires calibration.

Why Use WBGT as a Heat Stress Indicator vs. just using the Heat Index?

Wet bulb globe temperature (WBGT) is based on an equation that uses a combination of environmental elements to calculate the reading. The calculation is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation).

Heat index takes into consideration temperature and humidity, and is calculated for shady areas.

Customized Warning Zones

Users from different work environments or different standards around the world have the ability to create their own warnings on the Kestrel 4400.  With the user friendly functionality, the user may  go into the Kestrel 5400’s WBGT function and turn different warning zones on or off and set these warning zones to be triggered at different degrees as the temperature rises. By customizing the Kestrel 5400’s WBGT warning zones, monitoring a team or crew becomes much more personal. A chart with suggested warning zones will be included with every Kestrel 5400 ordered.

Whats New:

As for weather reading features, they will be the same.  You won’t get a ‘better’ temperature reading, wind reading, etc, or even more readings than available on the 4400/4600… still the same quality USA made meter backed by a 5 year warranty.  That being said there are some pretty outstanding updates.

  • Flag warnings via loud buzzer & LED beacon!
  • Bluetooth LINK works with PC/Mac via Dongle
  • Bluetooth LINK to Smartphones / Mobiel / Android / IOS
  • Takes 1 AA battery (instead of 2 AAA)
  • Battery door is in the back, sealed away from the motherboard, should your battery leak as was common with all the 4000 series.  All 5000 battery doors are the same and interchangeable.
  • Slightly larger and improved higher contrast / resolution screen for any lighting (even sunlight) and easy on your eyes.
  • Intuitive user-interface screen navigation
  • Multiple Languages (English, French, German, Spanish)
  • Scratch and breakage-resistant window
  • All meters include both options of Red (NV – Night Vision) & White backlights.
  • Slightly bigger, more robust, though not really noticeable difference.
  • Roughly 10,000 data points.  4000 series all had under 5000 data points.

Rotating Vane Mount and Carry Case, Kestrel 5 Series Overview

This precision engineered accessory securely mounts any Kestrel 5 Series meter to any tripod or other ¼-20 fitted bracket. Once mounted, the Kestrel 5 Series becomes a full-featured weather station with a large wind vane and precision pivot that keeps the Kestrel oriented into the wind for continuous measurement and logging of wind speed, wind direction, and all other key weather parameters. The Kestrel 5 Series Vane Mount offers many improvements over the Kestrel 4 Series Vane Mount including a sturdier one-piece boom, easier assembly, more secure retention of the Kestrel meter, and the convenience of being able to also use the Kestrel mounting clip as a fixed ¼-20 compatible bracket, allowing use of an extension pole for taking wind or air flow readings.

For maximum functionality, choose a Kestrel with LiNK wireless data communication to accompany your Vane Mount. The Kestrel LiNK app displays the Kestrel’s real-time readings on a vivid, customizable dashboard, providing a remote weather station display that functions up to 300’ away (line of sight).

Your Kestrel 5 series meter can be conveniently stored and carried inside the Vane Mount pouch, making it the world’s most portable weather station.

The ENTIRE Kestrel + Vane Mount kit weighs just 10.5 ounces / 295 grams and measures just 2.5 x 3 x 8.5 inches / 6.5 x 7.5 x 22 cm. An internal battery loop secures extra AA batteries and a snap-strap on the rear secures the kit to your belt or pack.