Kestrel 2500 Weather Meter

$169.00

Nature can turn on you at a moment's notice. Predict what's headed your way with the perfect instrument for any outdoor activity.

Availability: In stock
SKU
0825
Please fill out the selections below to help us ensure that you're getting the most accurate product




 FREE US SHIPPING

Kestrel 2500 Weather Meter Overview


Environmental Measures
Altitude (Barometric)
Barometric Pressure
Temperature
Wind Chill
Wind Speed/Air Speed
Tips For Taking Accurate Measurements

The Kestrel 2500 Handheld Weather Meter measures wind and temperature with total accuracy, and has the added benefits of an air pressure sensor that provides altitude and barometric information. Kestrel 2500 technology enables you to follow changes in air pressure that help predict impending changes in the weather. Factor in the 2500's digital altimeter, and you have most of the weather information you need for outdoor activities ranging from model airplane flight to rifle practice. A quick compare chart of the basic models shows you the differences between several Kestrel models.

As with all Kestrels, the 2500's sensitive and user-replaceable impeller technology provides accurate wind speed info. Additionally, an external temperature sensor and waterproof casing allow you to gauge the temperature of water and snow, as well as the open air. A hard slide-on case, lanyard, and battery are included.

The Kestrel 2500 was originated as a basic model for long range shooters at an affordable price and someone who didn't need the ballistic features built in like the 5700 Elite or any others in the Kestrel Ballistics Line of meters. A simple video shows how to achieve station pressure with a Kestrel 2500.

For those using it at night, the Olive Drab NV version of the Kestrel 2500 features a night-vision preserving backlight. This backlight incorporates an optical filter to reduce overall brightness and minimize blue and green spectrum light to preserve night vision. (Note: This backlight appears soft greyish pink, not "red", and is still in the visible spectrum, so is not compatible with night-vision equipment.)

Features of the Kestrel 2500 Weather Meter

  • Real-time clock
  • Protective cover with sure-grip over molding
  • Data hold function
  • Large easy-to-read display with white backlight (or soft red backlight on the NV model)
  • Waterproof to IP67 Standards (Can be submerged up to 3'/1M for up to 30 minutes)
  • Innovative design for stability and accuracy in abrupt condition changes
  • Patented user-replaceable impeller
  • Quick response, external thermistor
  • High precision pressure sensor
  • Reliable, portable, and easy to use
  • All instruments and accessories are completely assembled in the USA
  • 5 year warranty
  • Date & Time
  • Drop-Tested to MIL-STD-810G
  • High Contrast, Sunlight Readable Monochrome LCD Display
  • Minimum/Maximum/Average Reading
  • Pressure Sensor
  • Temperature Sensor (Patented External Isolated)
  • Waterproof to IP67 (3'/1M for 30 minutes)
  • Battery - 1 x CR2032
  • Certificate Of Conformity (Spec Sheet)
  • Instructions
  • Lanyard
  • Protective Cover - Hard Slip-on
SENSORS
SENSORS 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
3
5
5
0
F
W
3
5
5
0
A
G
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE OP. RANGE NOTES
Wind Speed | Air Flow Larger of 3% of reading, least significant digit or 20 ft/min 0.1 m/s
1 ft/min
0.1 km/h
0.1 mph
0.1 knots
1 B*
0.1 F/S*
0.6 to 40.0 m/s
118 to 7,874 ft/min
2.2 to 144.0 km/h
1.3 to 89.5 mph
1.2 to 77.8 knots
0 to 12 B*
2-131.2 F/S*
0.6 to 60.0 m/s
118 to 11,811 ft/min
2.2 to 216.0 km/h
1.3 to 134.2 mph
1.2 to 116.6 knots
0 to 12 B*
2-196.9 F/S*
1 inch|25 mm diameter impeller with precision axle and low-friction Zytel® bearings. Startup 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 startup. Off-axis accuracy -1% @ 5º off-axis; -2% @ 10º; -3% @ 15º. 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). Wind speed calibration and testing should be done with triangle on impeller located at the top front face of the Kestrel. *F/S only in Ballistics units. Beaufort not available in Ballistics units.
Ambient Temperature 0.9 °F
0.5 °C
0.1 °F
0.1 °C
-20.0 to 158.0 °F
-29.0 to 70.0 °C
14.0.0 to 131.0 °F
-10.0 to 55.0 °C
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 insolation effect. Calibration drift negligible. Thermistor may also be used to measure temperature of water or snow by submerging thermistor portion into material -- remove impeller prior to taking submerged measurements and ensure humidity sensor membrane is free of liquid water prior to taking humidity-based measurements after submersion.
Relative Humidity 3.0 %RH 0.1 %RH 5 to 95%
non-condensing
0 to 100% 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. Humidity sensor may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802).
Pressure 1.5hPa|mbar
0.044 inHg
0.022 PSI
0.1 hPa|mbar
0.01 inHg
0.01 PSI
25°C/ 77°F
750-1100 hPa|mbar
22.15-32.48 inHg
10.88-15.95 PS
0.30 to 48.87 inHg
10.0 to 1654.7
hPa|mbar
0.14 to 24.00 PSI
and
14.0 to 131.0 °F
-10.0 to 55.0 °C
Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Pressure sensor may be recalibrated at factory or in field. Adjustable reference altitude allows display of station pressure or barometric pressure corrected to MSL. Kestrel 4200 displays station pressure on a dedicated screen. 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. PSI display on Kestrel 4000 series only.
Compass
1/16th Cardinal
Scale
0 to 360° 0 to 360° 2-axis solid-state magnetoresistive sensor mounted perpendicular to unit plane. Accuracy of sensor 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). Readout indicates direction to which the back of the unit is pointed when held in a vertical orientation. Declination/variation adjustable for True North readout.
CALCULATED MEASUREMENTS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
3
5
5
0
F
W
3
5
5
0
A
G
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE SENSORS EMPLOYED NOTES
Altitude typical:
23.6ft/7.2m
max:
48.2ft/14.7m
1ft
1m
typical:
750 to 1100 mBar
max:
300 to 750 mBar
Pressure User Input (Reference Pressure) Height above Mean Sea Level ("MSL"). Temperature compensated pressure (barometric) altimeter requires accurate reference barometric pressure to produce maximum absolute accuracy. Both accuracy specs corresponds to a reference pressure anywhere from 850 to 1100 mBar.
Barometric Pressure 0.07 inHg
2.4 hPa|mbar
0.01 inHg
0.1 hPa|mbar
Refer to Ranges for Sensors Employed Pressure User Input (Reference Altitude) Air pressure that would be present in identical conditions at MSL. Station pressure compensated for local elevation provided by reference altitude. Requires accurate reference altitude to produce maximum absolute accuracy
Delta T 3.2 °F
1.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Difference between dry bulb temperature and wet bulb temperature. When spraying, indicates evaporation rate and droplet lifetime. Safe range for pesticide spraying is 4 to 16 °F / 2 to 9 °C.
Dew Point 3.4 °F
1.9 °C
0.1 °F
0.1 °C
15 to 95 % RH
Refer to Range for Temperature Sensor
Temperature Relative Humidity Temperature that a volume of air must be cooled to at constant pressure for the water vapor present to condense into dew and form on a solid surface. Can also be considered to be the water-to-air saturation temperature.
Heat Index 7.1°F
4.0°C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature Relative Humidity Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. Measurement range limited by extent of published tables
Temperature Humidity Index - THI (NRC) 1.5°F
0.8°C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature Relative Humidity
Temperature Humidity Index - THI (Yousef) 2.3°F
1.3°C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature Relative Humidity
Wet Bulb Temperature - Psychrometric 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Temperature indicated by a sling psychrometer. Due to nature of the psychrometric ratio for a water-air system, this approximates the thermodynamic wet-bulb temperature. The thermodynamic wet-bulb temperature is the temperature a parcel of air would have if cooled adiabatically to saturation temperature via water evaporating into it.
Wind Chill 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
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 10m above ground. Measurement range limited by extent of published tables.
ADDITIONAL SPECIFICATIONS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
3
5
5
0
F
W
3
5
5
0
A
G
NOTES
Display & Backlight Reflective 3 1/2 digit LCD. Digit height 0.36 in / 9 mm. Aviation green electroluminescent backlight. Manual activation with auto-off
Reflective 5 digit LCD. Digit height 0.36 in / 9 mm. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Manual activation with auto-off.
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.
Max/Avg Wind One-button clear and restart of Max Wind Gust and Average Wind measurement.
Data Upload & Bluetooth® Data Connect Option Requires optional PC interface (USB or RS-232) or Bluetooth data transfer option and provided software.
Bluetooth Data Transfer Option: Adjustable power consumption and radio range from up to 30 ft | 9 meters. Individual unit ID and 4-digit PIN code preprogrammed for easy identification and data security when pairing and transmitting. Employs Bluetooth Serial Port Protocol for data transmission.
Clock / Calendar Real-time hours:minutes clock.
Auto Shutdown After 45 minutes of no key presses.
Languages English
Certifications CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).
Origin Designed and manufactured in the USA from US and imported components. Complies with Regional Value Content and Tariff Code Transformation requirements for NAFTA Preference Criterion B.
Battery Life CR2032, one, included. Average life, 300 hours. Battery life reduced by backlight use in 2000 to 3500 models.
Shock Resistance MIL-STD-810g, Transit Shock, Method 516.6 Procedure IV; unit only; impact may damage replaceable impeller.
Sealing Waterproof (IP67 and NEMA-6).
Operational Temperature Limits 14° F to 131° F | -10 °C to 55 °C Measurements may be taken beyond the limits of the operational temperature range of the display and batteries by maintaining the unit within the operational range and exposing it to the more extreme environment for the minimum time necessary to take reading.
Storage Temperature -22.0 °F to 140.0 °F | -30.0 °C to 60.0 °C.
Size & Weight 4.8 x 1.9 x 1.1 in / 12.2 x 4.8 x 2.8 cm, 3.6 oz / 102 g (including slip-on cover).

* NOTE: Accuracy calculated as uncertainty of the measurement derived from statistical analysis considering the combined effects from primary sensor specifications, circuit conversions, and all other sources of error using a coverage factor of k=2, or two standard deviations (2Σ).

Kestrel Basic (1000-3500) Certificates of Comformity

Certificate of Conformity for the Kestrel 1000-3500DT with SNs above 2262687


Models & SKUs:

  • Kestrel 2500: 0825
  • Kestrel 2500 with Night Vision: 0825NV

Support Documents for all Kestrels

Replacing the Kestrel Impeller

Product Safety and Warranty Kestrel 5000 Series

Kestrel Basic (1000-3500) Certificates of Comformity

Certificate of Conformity for the Kestrel 1000-3500DT with SNs above 2262687

EMC DECLARATION OF CONFORMITY 2500, 2500NV, 3500, 3500NV

Kestrel 5 Series Troubleshooting Documents

Here is guidance on how to submit an order through the website for Tax Exempt customers.

Kestrel Basic (1000-3500) Instruction Manuals

User Guide for the Kestrel 1000, 2000, 2500, 2500NV, 3000, 3500, 3500NV, 3500DT, and 3500FW

Product Questions

"All measurements not available in all units"

Temperature Functions

For best accuracy when taking temperature measurements you must keep the air moving around the temperature sensor and keep the Kestrel out of prolonged, direct sunlight. If there is a strong breeze, just point the Kestrel into the wind. If there is no wind, swing the Kestrel around in a circle on its lanyard or rapidly wave it back and forth in hand. This ensures that the sensor measures the temperature of the air rather than the temperature of the case. Alternatively, if you have time, allow the Kestrel to rest where you want to measure the air temperature (NOT in your hand or in direct sunlight if there is no wind) until the case temperature equalizes with the air temperature. When equalized, the display will read a constant value. Be aware that this could take a few minutes, particularly if there is no wind.

Humidity Functions

One reason your Kestrel may not be reading accurate ambient humidity is because of proximity to humidity sources such as your hand, your body or the ground. Avoid covering the large humidity chamber opening on the case rear with your fingers. Keep all fingers below the finger groove and away from the chamber opening. Do not take reading that rely upon humidity with the Kestrel meter lying flat – raise it into the air vertically or stand it on its base and orient it into the wind or air flow. If a high level of accuracy is required for measurements involving humidity, do not hold the unit while taking measurements. Taking readings with the Kestrel in your hand or over your body can raise relative humidity by 5% or more. A Kestrel vane mount will isolate the Kestrel Meter from erroneous humidity influences and keep it oriented into the wind or air flow while taking measurements. Whenever you move your Kestrel Meter into a new environment wait until the primary sensor values have stabilized (Temperature, Humidity, etc.) before taking measurements that rely upon these values. After a large change in environmental condition, this may take 15 minutes or more, with humidity potentially taking the longest. If the humidity sensor housing (located above the rear label) is wet, the Kestrel cannot take an accurate humidity reading. If the sensor does become wet, shake the unit vigorously to remove the water, and then let it dry completely before use. If the sensor comes in contact with salt water, rinse it thoroughly with clean water, then shake it and allow it to dry. As is typical with humidity sensors, it is possible for the humidity sensor in the Kestrel to drift over time as described in the spec sheet. If your unit has a Humidity recalibration function, it can be returned to the factory or used with the Kestrel RH Calibration Kit to recalibrate its humidity readings.

Wind Meter Functions

Wind speed is highly dependent on surrounding obstructions such as buildings, yourself and the ground, with wind speeding up as it flows around and over obstacles and slowing down as it passes behind them. Even in an open area, Wind speed will be slower near the ground so ensure you are taking measurements at an appropriate height for your application. Hold the back of the unit directly into the wind. Holding the unit off-axis by 5° will reduce accuracy by 1%, 10° will reduce accuracy by 2% and 15° will reduce accuracy by 3%. Using a Kestrel Vane Mount will ensure the unit is correctly oriented into the wind and measuring accurate wind speeds. The Kestrel impeller housing can rotate in the unit. For best accuracy, ensure one of the three “arms” of the impeller housing is pointing straight up. The wind speed displayed by the Kestrel Meter is a 3 second rolling average. This allows the unit to provide a value that is more representative of the typical, ambient conditions but not capture peak speeds for instantaneous blasts of air.

Compass Functions

The compass in the Kestrel Meter is used for direction, crosswind, headwind/tailwind as well as for capturing various user inputs based on direction. When calibrating and when using the compass, it is important to hold the unit as vertically as possible. Any tilt in angle present when the unit is calibrated or when measurements are taken will negatively impact the accuracy of the compass reading. Many users will inadvertently tilt the Kestrel Meter away from themselves slightly when holding the unit. If a high level of accuracy is required, using a Kestrel vane mount on a leveled tripod for calibration and measurement can eliminate error.

Pressure Functions

All pressure and altitude measurements are made using the pressure sensor. Some units have a dedicated “Pressure” screen which shows Station Pressure, the raw pressure reading straight from the sensor. The Barometric Pressure measurement (Baro) displays the local Barometric Pressure using the Station Pressure measurement adjusted to the local altitude using the Reference Altitude value input by the user. The Altitude measurement displays the local altitude using the Station Pressure measurement combined with the Reference Baro value input by the user. To obtain an accurate barometric pressure or altitude readings, you must first know EITHER your location’s current barometric pressure OR your current altitude. If the Reference Altitude value is incorrect, the Barometric Pressure reading will also be incorrect. If the Reference Barometric pressure value is incorrect, the Altitude reading will also be incorrect. Because Barometric Pressure and Altitude are each dependent on the alternate reference value remaining constant, Barometric Pressure and Altitude cannot be accurately measured simultaneously. If your unit has a pressure recalibration function, a new Barometric Pressure calibration value may be input. If this value was not taken from a verified source (a local airport or weather station) with the Kestrel being calibrated at the same location as the reference device, pressure related measurements may be incorrect.

WBGT

When changing environments (such as moving form an air conditioned room to outdoors or removing the unit from your pocket) the unit requires between 8-15 minutes to equilibrate to its surroundings before taking readings. Take measurements at least 3 feet off the ground and in the same wind or air flow conditions as the people you are monitoring. Ensure the Kestrel is oriented into the wind and able to measure the full wind value. A tripod or pole mount and the Kestrel Rotating Vane Mount are ideal for ensuring accurate measurements. Differences in the reflectivity of ground surfaces such as grass or asphalt will impact measurements. Be sure to take measurements in the same solar/radiant heat environment as the people you are monitoring. Unlike best practices for other measurements, WBGT is intended to be taken in direct sunlight. As long as there is occasional wind the Kestrel has software that allows it to maintain an accurate WBGT reading despite being placed in direct sunlight.

Air Flow

Kestrel Professional Meters can calculate air flow through a duct by combining user input information about the size and shape of the duct with the measured air velocity. In addition to reading the instantaneous Air Flow off the main measurement screen, a more accurate result may be obtained by capturing an average air flow on the Min/Ave/Max screen while traversing the duct. Traversing consists of dividing the area of the duct into evenly sized sections and averaging the air flows at the center of all sections. By spending an equal amount of time at each measurement location and quickly moving between measurement locations, the average air flow measurement can provide a more accurate measure of the air flow in the duct. Capturing an average can be particularly helpful when measuring ducts with registers or dimensionally uneven air flow.

Air Flow Diagram

Evaporation Rate

(Kestrel 5200 Professional Environmental Meter) Kestrel Professional Meters can calculate a concrete evaporation rate (ACI 308) by combining a user input concrete temperature with measured air temperature, wind speed and relative humidity. Concrete mix temperature is generally measured with a probe or infrared thermometer and should be read at the time of making the evaporation rate measurement After inputting the mix temperature, hold the unit vertically, approximately 20 inches above the surface of the concrete while facing the rear of the unit directly into the wind. To avoid inaccurate Evaporation Rate readings due to thermal loading it is best to shade the Kestrel. (Be sure the source of shade is not obstructing the wind speed measurement.) The ACI recommends taking a 6-10 second average of the evaporation rate to account for fluctuating wind speeds. To measure an average Evaporation Rate, scroll right from the Evaporation Current Measurement Screen to the Min/Ave/Max Screen and press select to manually start and stop a capture.

... Permalink

Yes. You can always trade-in an older Kestrel, regardless of its condition, by using our Customer Trade-In Program.

... Permalink
  1. Start with a known; either current barometric pressure or current altitude. (NK recommends identifying your current altitude since it is constant.)
  2. Enter this reference altitude on the barometric pressure screen.
    • For K1000-K3500 you would enter this by pressing both outside buttons.
  3. Take note of the updated barometric pressure that is shown.
  4. Use this updated barometric pressure as your reference pressure on the altitude screen.
  5. Now your barometric pressure and altitude are set for your current location/conditions. Important note: If you change altitude the barometric pressure will become inaccurate. If a weather system moves in, the altitude will become inaccurate.

For more info check out our YouTube video on Setting Reference Pressure and Reference Altitude on the Kestrel 4000 series!

... Permalink
  1. How Barometric Pressure Influences Winter Fishing How Barometric Pressure Influences Winter Fishing While many of us imagine fishing on hot and lazy summer days, plenty of people head to the nearest fishing spot for a wintertime catch. Are you looking to take your game to the next level? Put down your lures and pull out the barometric pressure gauge! Learning how barometric pressure influences fish behavior can give you an edge over all other anglers on the lake. The Kestrel DROP D3 data logger makes it easy to monitor barometric pressure
  2. Barometric Pressure vs. Station Pressure: What's the Difference? Barometric Pressure vs. Station Pressure: What's the Difference? When it comes to measuring barometric pressure, there is a bit of science going on behind the scenes. Let's take a look at the difference between barometric vs. station pressure and the variables that go into calculating the two readings.
  3. The Importance of Weather Monitoring for Vegetation Management The Importance of Weather Monitoring for Vegetation Management When it comes to vegetation management, environmental factors play an important role in success or failure. Planning and preparation become critical, especially when it comes to the knowing the weather conditions before and during spray application. With Kestrel weather meters, you can accurately track weather with real-time data, allowing you to make smart decisions for planning and application.
  4. Why Weather Meters Outperform Weather Apps for Accuracy Measurements Why Weather Meters Outperform Weather Apps for Accuracy Measurements When you check the forecast on a weather app, you'll find that it doesn't necessarily offer the most accurate information for your specific location. Many times the weather app will call for rain, yet you don’t see a drop the entire day. Kestrel weather & environmental meters are superior to most weather apps on the market, and one of the secrets behind it's accuracy boils down to microclimates.
  5. Improve Your Fishing Strategy with Kestrel 2500 Pocket Weather Meter Whether you enjoy fishing for stress relief or you’re a seasoned pro, the Kestrel 2500 pocket weather meter can help improve your overall fishing strategy. While baiting a hook with a worm and casting it into the water is a simple approach, the Kestrel 2500 can take your fishing game to the next level.