Garden with Insight v1.0 Help: Weather station values group
Barometric pressure: The barometric pressure for
the weather station of this climate. This is calculated only once when a climate is chosen and depends
only on weather site elevation above sea level.
Psychrometric constant: Used in the calculation of evapotranspiration. Depends only on barometric pressure; calculated only
Slope of the saturation vapor pressure curve: The slope of the curve generated by plotting mean temperature versus saturation vapor pressure. Recalculated daily and
used in calculating potential evapotranspiration.
Probability of wet day by month: Simply the number of wet days per month divided by the
number of days in each month. Used in various places as an indication of the wetness of the climate, but
not used to generate actual rainfall.
Mean daily precipitation by month: Long-term monthly averages for daily precipitation (rain
and snow). Used (with autocorrelation) to generate simulated daily
precipitation values, if the simulated day is a 'wet day'. Determination of wet days is done by monthly
Minimum day length for the year: The shortest day length for
the year for this climate.
Factor to normalize skewed normal rainfall distribution: An
adjustment factor multiplier for each day's rainfall to normalize (keep
within reasonable bounds) the 'skewed normal' rainfall distribution from which daily rainfall values are
selected. Calculated by iteration with the skewed normal distribution.
Maximum possible radiation for year: The highest solar radiation possible on any clear day this
year. The greater of the maximum radiation on the two solstices (June and December). The maximum
radiation for each of these two days is calculated from latitude and the day of the year.
Day of first fall frost (days from January 1): The first day on which the average minimum
(night) temperature falls below freezing as winter approaches. Depends on the minimum temperatures for
each month; influences planting and harvest dates.
Day of last spring frost (days from January 1): The last day on which the average minimum
(night) temperature falls below freezing as summer approaches. Depends on the minimum temperatures
for each month; influences planting and harvest dates.