Hey John,
Since no one used AirTemperature as a condition before (not even me…), I just found out that the SODE xml code cannot handle negative values.
Visibilities and every other condition are only in the positive range, so this bug never popped up.
So thanks for reporting! 🙂
The next version will support negative values for air temperature, the prefix for negative numbers will be “M” for minus, because the dash can’t be used (reserved for ranges).
So “M6-4” will be the correct syntax.