Bug fix - In OS3 if the sensor was set to output in units of feet the visibility would still be interpreted as metres for the purpose of present weather identification causing reporting of fog and mist in SYNOP and METAR codes at too low visibility values. Visibility itself was reported correctly. This is now fixed.
Present weather algorithm change - Addition of SYNOP and METAR codes for ice pellets.
Present weather algorithm change - Addition of visibility component to METAR codes for light precipitation, for example –RA FG would be reported for a combination of light rain and visibility reduced below 1000m.
Present weather algorithm change - Addition of a lower air temperature threshold between fog and freezing fog. Freezing fog will not be reported below -30.0 °C following guidance in ICAO 8896 2.3.11.9.