Field and Factory Recalibration

Not only is every Kestrel wind meter and weather station guaranteed accurate when it leaves the factory, but accuracy can be ensured by field and factory recalibration for years of reliable performance. Relative humidity, wind, and barometric pressure measurements on each Kestrel wind meter and weather station can be calibrated in the field, no matter how old the Kestrel wind meter and weather station.

Patented Dual Temperature Sensor RH Measurement

Relative humidity is tricky to measure—particularly in a sealed product. But, with wildland firefighters among our leading customers, we know it is essential to get it right. Accurate temperature measurement is critical to calculating relative humidity. With Nielsen-Kellerman's patented Kestrel wind meter and weather station dual temperature sensor, it's not necessary to wait the 20 to 40 minutes that would normally be required for the unit temperature to equilibrate to the air temperature after a temperature shift. The Kestrel wind meter and weather station instantly and accurately calculates relative humidity accuracy of +/- 3% RH from 5 to 95%.

The humidity sensor in the Kestrel wind meter and weather station has been selected for long-term stability and reliable performance even at very low and very high humidity conditions. Every Kestrel wind meter and weather station is calibrated against NIST-traceable standards, and can be recalibrated in the field with the Kestrel wind meter and weather station RH kit.

Patented Temperature Measurement

Unlike most watches and other products with a temperature measurement, the Kestrel wind meter and weather station sensor is outside the case to ensure it measures the air, not your hand or pocket. The "curls" serve to further isolate the temperature sensor from the effects of the case temperature. Simply wave the Kestrel wind meter and weather station back and forth a few times and you'll have accurate air temperature readings in seconds.

And, since the Kestrel wind meter and weather station is completely waterproof, you can actually take water temperature and snow temperature readings. Just ask the US Biathlon team—they used Kestrel wind meter and weather station 4000's in the 2006 Winter Olympics to measure air and snow temperature to determine the appropriate wax touse on their skis.

Leak and Drop Testing

A Kestrel wind meter and weather station is totally protected from dust and can be submerged in water to 1 m (3ft) for up to 30 minutes without any leakage.

US Manufacturing

The entire Nielsen-Kellerman Kestrel wind meter and weather station line is designed and built in the USA—no other handheld weather meter is.

Patented Removable Impeller

The Kestrel wind meter and weather station impeller measures 1 inch across and turns on a Swiss precision pivot mounted on sapphire bearings. Its large size ensures accurate readings even if pointed off-angle from the wind, and its very low start-up speed allows measurement of the lightest puffs of wind. Units with smaller impellers simply can't match the Kestrel wind meter and weather station's performance. If damaged, a new calibrated impeller can be purchased for $14.95 and popped in without tools, restoring like-new performance.

Pressure-Corrected Wet Bulb Temperature

Kestrel Wind Meters provide bulb temperature readings without a pressure sensor assume standard atmospheric conditions, leading to highly inaccurate readings on low-pressure days, at high altitudes, or in any other "non-standard" situation. Kestrel wind meter and weather station meters offer wet bulb temperature readings only on our pressure-sensor equipped units, ensuring accuracy in all conditions.