3
D e w p o i n t ( c a l c u l a t e d )
Resolution and Units ......................................................... 1°F or 1°C (user-selectable)
Range ............................................................................... -105° to +130°F (-76° to +54°C)
Accuracy ........................................................................... ±3°F (±1.5°C) (typical)
Update Interval.................................................................. 10 to 12 seconds
Source .............................................................................. World Meteorological Organization (WMO)
Equation Used .................................................................. WMO Equation with respect to saturation of moist air over water
Variables Used.................................................................. Instant Outside Temperature and Instant Outside Relative Humidity
Current Data ..................................................................... Instant Calculation; Daily, Monthly High and Low
Historical Data .................................................................. Hourly Calculations; Daily, Monthly, Yearly Highs and Lows
Alarms .............................................................................. High and Low Threshold from Instant Calculation
E v a p o t r a n s p i r a t i o n
( c a l c u l a t e d , r e q u i r e s V a n t a g e P r o 2 I S S w i t h s o l a r r a d i a t i o n s e n s o r
)
Resolution and Units ......................................................... 0.01" or 0.1 mm (user-selectable)
Range ............................................................................... Daily to 32.67" (999.9 mm); Monthly & Yearly to 199.99" (1999.9 mm)
Accuracy ........................................................................... Greater of 0.01" (0.25 mm) or ±5%, Reference: side-by-side
comparison against a CIMIS ET weather station
Update Interval.................................................................. 1 hour
Calculation and Source ..................................................... Modified Penman Equation as implemented by CIMIS (California
Irrigation Management Information System) including Net Radiation
calculation
Current Data ..................................................................... Latest Hourly Total Calculation, Daily, Monthly, Yearly Total
Historical Data .................................................................. Hourly, Daily, Monthly, Yearly Totals
Alarm ................................................................................ High Threshold from Latest Daily Total Calculation
F o r e c a s t
Variables Used.................................................................. Barometric Reading & Trend, Wind Speed & Direction, Rainfall,
Temperature, Humidity, Latitude & Longitude, Time of Year
Update Interval.................................................................. 1 hour
Display Format .................................................................. Icons on top center of display; displays weather conditions that may
occur for the next 12 hours.
Variables Predicted ........................................................... Sky Condition, Precipitation
H e a t I n d e x
( c a l c u l a t e d )
Resolution and Units ......................................................... 1°F or 1°C (user-selectable)
Range ............................................................................... -40° to +165°F (-40° to +74°C)
Accuracy ........................................................................... ±3°F (±1.5°C) (typical)
Update Interval.................................................................. 10 to 12 seconds
Source .............................................................................. United States National Weather Service (NWS)/NOAA
Formulation Used .............................................................. Steadman (1979) modified by US NWS/NOAA and Davis Instruments
to increase range of use
Variables Used.................................................................. Instant Outside Temperature and Instant Outside Relative Humidity
Current Data ..................................................................... Instant Calculation; Daily, Monthly High
Historical Data .................................................................. Hourly Calculations; Daily, Monthly, Yearly Highs
Alarm ................................................................................ High Threshold from Instant Calculation
H u m i d i t y
Inside Relative Humidity (sensor located in console)
Resolution and Units.................................................. 1%
Range........................................................................ 1 to 100% RH
Accuracy.................................................................... ±3% (0 to 90% RH), ±4% (90 to 100% RH)
Update Interval .......................................................... 1 minute
Current Data .............................................................. Instant (user adjustable) and Hourly Reading; Daily, Monthly High and
Low
Historical Data ........................................................... Hourly Readings; Daily, Monthly, Yearly Highs and Lows
Alarms ....................................................................... High and Low Threshold from Instant Reading
