Kestrel 4500 Weather Meter | RPR Ltd
Kestrel 4500 Weather Meter Kestrel 4500 Weather Meter Kestrel 4500 Weather Meter Kestrel 4500 Weather Meter
5-Year Warranty on all Kestrels

Kestrel 4500 Weather Meter

Product code: K4500 - 0845

This product is now discontinued. Superseded by the Kestrel 5500.

The Kestrel 5500 is £ (ex VAT) and available here »

The Kestrel 4500 Pocket Weather Tracker is a complete weather instrument (with Bluetooth), offering all the features of the Kestrel 4000 with instant and accurate measurement of wind speed, temperature, humidity and barometric pressure and numerous other derived functions.

In addition, the Kestrel 4500 has a built in digital compass. This allows you to track and log wind direction as well as wind speed. The wind direction is displayed in degrees and cardinal compass points. This makes the Kestrel 4500 the required model for HAZMAT teams, flight crews and military personnel as well as paragliders, flying enthusiasts and kite boarders who need to understand the impact of crosswind, headwind and tailwind.

The Kestrel 4500 range has now been superseded by the Kestrel 5500 range.

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By setting a reference target or runway heading, the Kestrel 4500 will automatically calculate crosswind, headwind and tailwind when measuring the wind speed.

The digital compass can also be used to display forward heading with reference to either magnetic or true north.

Coupled with the Kestrel Vane Mount and Mini Tripod the Kestrel 4500 becomes a full data-logging weather station measuring the slightest of breezes. All items are easily portable and can be set up in seconds.

At the touch of a button environmental conditions are clearly shown in digital or graphical form. Individual functions can be displayed in three different formats: current, minimum/maximum/average and chart. There are also three user screens, which can be customised to simultaneously display the three most appropriate functions for the application.

The Kestrel 4500 can be set up to log data automatically (as well as manually) at programmable intervals, in order to display a history of weather information. Graphs display up to 2900 data points and the value, time and date of capture point can be shown.

The stored data can also be uploaded to a PC, for analysis/storage with the optional Kestrel Interface and Communicator software. With the Bluetooth model, data may be streamed live via Bluetooth wireless technology.

High precision Zytel bearings and a lightweight impeller provide accurate air flow measurements and the ability to operate at speeds as low as 0.6 m/s. The impeller is user-replaceable in case of damage, also ensuring high accuracy levels are maintained for life. An integral flip-open hard cover protects the impeller when not in use.

A precision external thermistor sensor provides fast response temperature readings and accuracy of +/- 1°C. The 0.1 degree resolution of the display aids in determining when a consistent reading has been reached. A special housing protects the relative humidity sensor from contamination providing an accuracy of +/-3%. A monolithic silicon based pressure sensor enables barometric pressure and altitude to be calculated, with a resolution of 0.1mbar and 1m respectively.

The combination of the Kestrel 4500 Pocket Weather Tracker's multiple sensors result in the following derived functions: wind chill, heat index, dew point, wet bulb temperature and density altitude.

For those with after dark requirements, the Kestrel 4500NV (with an olive drab case) is available with a low intensity red backlight to preserve night vision.

The Kestrel 4500 is powered by two easily replaceable, AAA batteries and has two power saving modes to prolong battery life. All text can be displayed in one of several languages including: English, French, Italian, Spanish or German.

Kestrel 4500 measures
  • Current wind speed
  • Average wind speed
  • Maximum wind speed
  • Wind direction
  • Crosswind
  • Headwind/tailwind
  • Temperature
  • Wind Chill
  • Heat index
  • Dew Point
  • Relative Humidity
  • Barometric pressure
  • Altitude
  • Density altitude
  • Wet bulb temperature
  • Digital compass
  • Time & Date
Choice of measurement units
  • kt, m/s, km/h, mph, ft/min, Beaufort
  • °, cardinal points
  • °C, °F
  • %
  • mbar, inHg, hPa, psi
  • m, ft
  • Speed ±3% of reading or ±0.1m/s
  • Direction ±5°
  • Crosswind, headwind, tailwind ±5%
  • Temperature ±1°C
  • Relative humidity ±3%
  • Dew point ±2°C
  • Barometric pressure ±1.5mbar
Operational Range
  • Speed 0.6 to 60 m/s
  • Direction 360°
  • Crosswind, headwind, tailwind 0.6 to 60 m/s
  • Temperature -45 to +125°C
  • Relative humidity 0 to 100%
  • Barometric pressure 10 to 1100mbar
Specification Range
  • Speed 0.6 to 40 m/s
  • Direction 0 to 360°
  • Crosswind, headwind, tailwind 3.8 to 40 m/s
  • Temperature -29 to +70°C
  • Relative humidity 5 to 95%
  • Barometric pressure 750 to 1100mbar
Available options
Kestrel 4500 features
  • Multifunction instrument
  • Graphical three-line displays
  • Data capture up to 2900 readings
  • Minimum/maximum/average values
  • User defined screens
  • Language selection
  • Compact, rugged design
  • High accuracy
  • High precision axle and low-friction Zytel bearings
  • User-replaceable impeller
  • Fast response temperature sensor
  • Easy to read back-lit display
  • NV version in olive drab or desert tan has red backlight
  • Hard cover protects impeller
  • Runs from 2 AAA batteries
  • Data upload (with optional PC interface or integrated Bluetooth wireless technology)
  • Available in yellow, olive drab or desert tan
  • 5 year warranty
Typical applications
Primary Measurement Units Resolution Accuracy
(if less)
Wind Speed
or Air Velocity
m/s 0.1 Larger of 3% of reading, least significant digit or 20 ft/min 0.6 to 60.0 m/s
0.6 to 40.0 m/s
1 inch diameter impeller with precision axle and low-friction Zytel® bearings.
Start-up speed stated as lower limit, readings may be taken down to 0.4 m/s | 79 ft/min | 1.5 km/h | .9 mph | .8 kt after impeller start-up.
Off-axis accuracy -1% @ 5° off-axis; -2% @ 10°; -3% @ 15°.
Calibration drift < 1% after 100 hours use at 16 MPH | 7 m/s.
Replacement impeller (NK PN-0801) field installs without tools (US Patent 5,783,753).
ft/min 1 18 to 11,811 ft/min
118 to 7,874 ft/min
km/h 0.1 2.2 to 216.0 km/h
2.2 to 144.0 km/h
mph 0.1 1.3 to 134.2 mph
1.3 to 89.5 mph
knots 0.1 1.2 to 116.6 knots
1.2 to 77.8 knots
Beaufort 1 0 to 12 B
Temperature °F 0.1 1.8 °F -49.0 to 257.0
-20.0 to 158.0
Air, water or snow temperature. Hermetically-sealed, precision thermistor mounted externally and thermally isolated (US Patent 5,939,645) for rapid response. Airflow of 2.2 mph | 1 m/s or greater provides fastest response and reduction of insulation effect. Calibration drift negligible.
°C 0.1 1.0 °C -45.0 to 125.0
-29.0 to 70.0
Relative Humidity %RH 0.1 3.0 %RH 0.0 to 100.0%
5.0 to 95.0% non-condensing
Polymer capacitive humidity sensor mounted in thin-walled chamber external to case for rapid, accurate response (US Patent 6,257,074). To achieve stated accuracy, unit must be permitted to equilibrate to external temperature when exposed to large, rapid temperature changes and be kept out of direct sunlight. Calibration drift +/- 2% over 24 months. RH may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802).
Pressure inHg 0.01 typical 0.04 inHg
max 0.07 inHg
0.30 to 32.48 inHg Air pressure at the location. Adjustable reference altitude allows display of station pressure or barometric pressure corrected to MSL. Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Pressure sensor may be recalibrated at factory or in field. Kestrel 2500 and 3500 display continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly. Kestrel 4000 series displays pressure trend through graphing function.
hPa (mb) 0.1 typical 1.5 hPa
max 2.5 hPa
300.0 to 1100.0 hPa 10.0 to 1100.0 hPa
PSI 0.01 typical 0.02 PSI
max 0.04 PSI
0.14 to 15.95 PSI
Wind Direction
Forward Heading
° 1 0 to 360° 2-axis solid-state magnetoresistive sensor mounted perpendicular to unit plane to permit operation while measuring wind speed. Declination/variation adjustable for True North readout. Accuracy of measurements dependent upon unit's vertical position. Self-calibration routine eliminates magnetic error from batteries or unit and must be run after every full power-down (battery removal or change).
Cardinal 16 Points 0 to 360°
Crosswind &
mph 1 10% Refer to stated ranges for wind speed. Effective wind relative to a target or travel direction. Calculated from wind speed, wind direction and target heading. Auto-switching headwind/tailwind indication.
ft/min 1 10%
km/h 0.1 10%
m/s 0.1 10%
knots 0.1 10%
Wind Chill °F 0.1 1.8 °F Refer to stated ranges for wind speed and temp. Perceived temperature resulting from combined effect of wind speed and temperature. Calculated based on the NWS Wind Chill Temperature (WCT) Index, revised 2001, with wind speed adjusted by a factor of 1.5 to yield equivalent results to wind speed measured at 10 m above ground. Specification temperature limits established by WCT Tables.
°C 0.1 1.0 °C
Heat Index °F 0.1 3.6 °F Refer to stated ranges for temp. and relative humidity. Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. (Specification temperature limits established by HI tables.)
°C 0.1 2.0 °C
Wet Bulb Temperature (Psychrometric) °F 0.1 3.6 °F Refer to stated ranges for temp., relative humidity and pressure. Temperature indicated by a wet bulb psychrometer under forced aspiration. Calculated from temperature, relative humidity and pressure.
°C 0.1 2.0 °C
Dewpoint °F 0.1 3.6 °F Refer to stated ranges for temp. and relative humidity. Temperature to which the air must be cooled at a constant pressure for water vapour to condense into water. Calculated from temperature and relative humidity.
°C 0.1 2.0 °C
Altitude ft 1 typical 50 ft
max 98 ft
-2,300 to 85,000 ft Height above Mean Sea Level ("MSL"). Temperature compensated pressure (barometric) altimeter requires accurate reference barometric pressure to produce maximum absolute accuracy.
m 1 typical 15 m
max 30 m
-700 to 25,900 m
Density Altitude ft 1 246 Refer to stated ranges for temp., relative humidity and pressure. Air density converted to equivalent sea level elevation at the International Standard Atmosphere. Calculated from temperature, pressure and relative humidity.
m 1 75
Max/Avg Wind Max and average wind calculation may be started and stopped independently of data logging of other values, along with all other wind-related functions: air velocity, crosswind, headwind/tailwind, wind chill, WBGT, TWL, evaporation rate.
Data Storage & Graphical Display, Min/Max/Avg History Minimum, maximum, average and logged history stored and displayed for every measured value. Large capacity data logger with graphical display. Manual and auto data storage. Min/Max/Avg history may be reset independently. Auto-store interval settable from 2 seconds to 12 hours, overwrite on or off. Logs even when display off except for 2 and 5 second intervals (code version 4.18 and later). Data set capacity = 2900.
Data Upload Requires optional PC interface (USB or RS-232) or Bluetooth enabled model and provided software.
Available Bluetooth®
Data Connect
Adjustable power consumption and radio range from up to 30 ft | 9 meters. Individual unit ID and 4-digit PIN code pre-programmed for easy identification and data security when pairing and transmitting. Employs Bluetooth Serial Port Protocol for data transmission.
Display & Backlight Multifunction, multi-digit monochrome dot-matrix display. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Automatic or manual activation.
Response Time & Display Update All measurements except those based on relative humidity respond accurately within 1 second. Relative humidity and all measurements which include RH in their calculation may require as long as 1 minute to fully equilibrate to a large change in the measurement environment. Display updates every 1 second.
Clock / Calendar Real-time hours:minutes:seconds clock, calendar, automatic leap-year adjustment.
Operational & Storage Temperature Range The operational temperature range of the liquid crystal display and batteries is 14° F to 131° F / -10 °C to 55 °C. Measurements beyond the operational range can be taken by briefly exposing unit to extreme conditions such that the display and batteries remain within the operational range. Storage range -22 °F to 140 °F / -30 °C to 60 °C.
Auto Shutdown User-selectable -- 15 or 60 minutes with no key presses or disabled.
Languages English, French, German, Italian, Spanish.
Certifications CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).
Battery AAA Alkaline, two, included. Average life, 400 hours of use, reduced by backlight or Bluetooth radio transmission use.
Environmental Waterproof (IP67 and NEMA-6). MIL-STD-810F, Transit Shock, Method 516.5 Procedure IV; unit only; impact may damage replaceable impeller.
Size & Weight 5.0 x 1.8 x 1.1 in / 12.7 x 4.5 x 2.8 cm, 3.6 oz / 102 g.
Colour Options Yellow | Olive Drab (NV version) | Desert Tan (NV version)

The manufacturer reserves the right to amend the specification and therefore the information in this document may be subject to change