DAVIS GroWeather Console - Manual (Page 15)

GroWeather System Overview
Page 8 GroWeather Manual
Air, Soil, and Apparent Temperature
The GroWeather uses the primary temperature sensor to measure the outside
air temperature. The second temperature sensor can be used to measure the
soil temperature or to measure the air temperature in a second location.
Although it is referred to as “soil” temperature, you may use this sensor to
measure whatever auxiliary temperature you see fit (including water tempera-
ture). In addition, the GroWeather calculates two apparent temperature read-
ings: temperature/humidity index (T-H Index) and wind chill.
The T-H Index uses the temperature and the relative humidity to determine
how hot the air actually “feels.” When humidity is low, the apparent tempera-
ture will be lower than the air temperature since perspiration can rapidly evap-
orate into the air. However, when humidity is high (i.e., the air is saturated
with water vapor) the apparent temperature will be higher than the air temper-
ature.
Note: The GroWeather measures T-H Index only when air temperature is above 68˚ F (20˚ C) because it
is a measure of heat stress, which is not significant at lower temperatures. 125˚ F (52˚ C) is the
highest T-H Index for which calculation factors are available. Above that, the system simply reports
that T-H Index is “high.”
Wind chill takes into account how the speed of the wind affects our perception
of the air temperature. The body warms up the air molecules which surround it
by transferring heat from the skin to the surrounding air. If the wind is com-
pletely still, this “insulating layer” of warm air molecules stays next to the
body, offering some protection from the cooler air molecules and limiting fur-
ther transfer of heat. When the wind is blowing, however, the warm air sur-
rounding the body is swept away. The faster the wind blows, the faster the heat
is carried away and the colder you feel.
• Current Outside Air Temperature (Alarm: High/Low)
• Current Soil Temperature (Alarm: High/Low)
• Current Temperature/Humidity Index (Alarm: High)
• Current Wind Chill (Alarm: Low)
• “Daily” High and Low Air Temperature with time and date of occurrence (Auto-
Clear)
• “Daily” High and Low Soil Temperature (AutoClear)
• “Daily” High Temperature/Humidity Index with time and date of occurrence
(AutoClear)
• “Daily” Low Wind Chill with time and date of occurrence (AutoClear)