Temperature and pressure can be seen directly in any of the G1000 equipped aircraft. I simply press the B key on the keyboard to sync the aircraft altimeter baro setting to the current external pressure. The default G1000 aircraft can also show wind direction and speed. The Working Title G1000 mod suppresses the display of wind on the ground, since the real G1000 can only calculate wind when the aircraft is in flight.
But, in my case I use a 3rd party developer tool that can directly monitor the simconnect atmospheric environment variables for ambient pressure, total and static air temperature, air density, wind direction, wind velocity, and pressure altitude. There is not (and never has been) a simconnect variable for dewpoint. Dewpoint is not something which any MS simulator (FSX, P3D or MSFS) is able to use directly, so the “dewpoint” reading in the ATIS is meaningless.
The METAR wind direction and speed is being injected into the sim environment exactly as reported. Now, the sim may be applying a gust factor to that value that changes the aerodynamic effect on the flight model. The tool I use will not show that.
The ATIS report of temperature and pressure appear to correspond to what is being injected. A gust factor may be applied to injected winds. ATIS reports of clouds, precipitation and dewpoint appear to be completely fictitious. They have nothing to do with the actual weather in the sim environment, with the possible exception of the very lowest cloud layer when conditions are overcast.
The simconnect variable for “visibility” is being set when live weather is active, and this appears to come from MeteoBlue, not the METAR. But, the sim (currently) appears to try to translate that to “particle density” rather than being able to use visibility directly in standard aviation units of miles/km or yards/meters. I have seen true low surface visibility in the sim on several occasions, but it appears to do that by simply placing a cloud layer on the surface.