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    Kestrel® 4300 Construction Weather Tracker


    Plastic Shrinkage Cracks are a costly problem for concrete professionals- they occur when the surface of the concrete dries quickly and shrinks before it is strong enough to resist cracking. Measuring relative humidity, ambient temperature and wind velocity at the pour site before the concrete is placed can help prevent this frustrating and expensive problem. Bluetooth® data transfer capabilities send minute by minute conditions during any pour straight to a laptop for easy jobsite documentation that conditions were within industry acceptable standards. The Kestrel 4300 Construction Pocket Weather Tracker is the perfect solution-accurate, quick response readings give concrete professionals the information they need to place concrete that won't crack.


    Kestrel 4300 Measures

    Evaporation rate

    Relative humidity in %

    Wind speed
    (current, average, and maximum)

    Temperature in °F or °C


    Barometric pressure

    Heat stress index

    Wet bulb temperature



    Density altitude

    Kestrel 4300 Features

    • Waterproof and floats
    • Backlight for low light conditions
    • Data logger (automatic and manual)
    • Customizable data storage – 3600 data points
    • Multi-Function 3-line display
    • Convenient averaging mode
    • Data charting
    • Humidity sensor can be recalibrated in the field with our Relative Humidity Calibration Kit.
    • User-replaceable impeller
    • Flip-top impeller cover
    • Upload to a computer (with optional interface)
    • Five languages (English, French, Spanish, German, and Italian)
    • US Patent Nos. 5,783,753 and 5,939,645 and 6,257,074
    • 5-year warranty
    • Assembled in the USA

    Kestrel 4300 Includes

    • Soft carry pouch
    • Neck lanyard
    • Batteries – 2 AAA
    • Kestrel Certificate of Conformity


    Calculates Evaporation Rate

    The new Kestrel 4300 Construction Weather Tracker measures and displays evaporation rate — a function of relative humidity, temperature and wind speed. Evaporation rate is a critical environmental indicator that concrete contractors use to ensure they avoid plastic shrinkage cracks in concrete installations especially concrete flatwork. Plastic shrinkage cracks occur when the surface of the concrete dries too quickly and shrinks before the bed has cured enough to resist cracking. This is especially relevant in specialty applications like decorative concrete, Ready Mix Concrete (RCM) and Tilt-up concrete.

    Helps Prevent Plastic Shrinkage Cracks

    Plastic shrinkage cracks can be prevented by properly assessing the weather and the fresh concrete conditions. Previously, construction contractors used a Kestrel Meter to measure the relevant conditions, then referenced an American Concrete Institute chart to calculate the evaporation rate. The new Kestrel 4300 Construction Weather Tracker does the work for them! The user simply enters the concrete temperature (obtained via an infrared thermometer or probe thermometer*) and the 4300 calculates the evaporation rate instantly. In addition to evaporation rate, the Kestrel 4300 remains the perfect rugged all-purpose construction weather tool, measuring and logging the following relevant weather conditions right where the workers and equipment are operating.

    For maximum accuracy when measuring the evaporation rate:

    • Measure the concrete temperature via an infrared or probe thermometer
    • Enter the concrete temperature into the Kestrel
    • Position the unit facing into the wind, 20 inches above the concret
    • Shade the Kestrel's thermistor (temperature sensor) so it is not in direct sunlight

    For the best accuracy, use the Kestrel's convenient averaging mode to average the evaporation rate over the recommended 6-10 seconds.

    Documents Work Conditions

    Many construction applications require documentation of conditions, which is quick and easy with the Kestrel PC Interface and accompanying software. Use the 4300's 1800 data-point log to document that work was done during the appropriate conditions, then upload the data to a PC with the Kestrel PC Interface. The Kestrel Communicator software makes long-term storage, in-depth analysis and detailed charting of stored data a breeze.

    Kestrel's Mini Tripod is a great companion for the 4300—it measures 15 inches tall, positioning the Kestrel 4300 20 inches above the concrete, which is ideal for measuring the conditions that contribute to plastic shrinkage cracks.

    Every Kestrel is individually calibrated to NIST-traceable standards and comes with a free Certificate of Conformity. Individual NIST certificates and recalibration are also available.