your location would be at if located at sea-level) is generally higher than your measured pressure.
Thus, your absolute pressure may read 28.62 inHg (969 mb) at an altitude of 1000 feet (305 m), but the relative
pressure is 30.00 inHg (1016 mb).
The standard sea-level pressure is 29.92 in Hg (1013.2hpa). This is the average sea-level pressure around the
world. Relative pressure measurements greater than 29.92 inHg (1013.2hpa) are considered high pressure and
relative pressure measurements less than 29.92 inHg are considered low pressure.
To determine the relative pressure for your location, locate an official reporting station near you (the internet is the
best source for real time barometer conditions, such as Weather.com or Wunderground.com), and set your weather
station to match the official reporting station.
6. Wind+Gain+Calibration+
Press the SET button and the wind gain will flash. The default is 1.00 (the display will show 100 but it is actually
1.00. There is no provision for the decimal point).
Press the [+] or [-] button to adjust the wind speed calibration factor from 0.75 to 1.25, where:
Calibrated Wind Speed = Calibration factor x Measured Wind Speed
Press and hold the [+] or [-] button for three seconds to increase or decrease rapidly.
Press the ALARM button to reset current value.
Note: The wind gust is also affected by the wind speed calibration factor.
Discussion: Wind speed and wind gust are adversely affected by installation constraints. The rule of thumb is
to install the weather station four times the distance of the height of the tallest obstruction (for example, a 6 m
house would require an installation 24 m away).
In many instances, due to trees and other obstructions, this is not possible. The wind speed calibration allows you
to correct for these obstructions.
In addition to installation challenges, wind speed bearings (any moving part) wears over time. To correct for wear,
the correction value can be increased until the wind cups must be replaced.
Without a calibrated source, wind speed is a difficult parameter to measure. We recommend using a calibrated
wind meter and constant, high speed fan.
7. Rain+Calibration+
Press the SET button again and the Rain Calibration value will begin flashing (the default is 1.0). Press the [+] or
[-] button to adjust the rain calibration factor from 0.75 to 1.25, where:
Calibrated Rain = Calibration factor x Measured Rain
Press and hold the [+] or [-] button for three seconds to increase or decrease rapidly.
Press the ALARM button to reset current value.
Discussion: The rain collector is calibrated at the factory based on the funnel diameter. The bucket tips every
0.01” of rain (referred to as resolution). The accumulated rainfall can be compared to a sight glass rain gauge with
an aperture of at least 4”.
Note: that debris and insects can collect inside the tipping mechanism (they make a good spiders nest).
Carefully remove the funnel and inspect the tipping mechanism for debris prior
to calibration.
