I use Active Sky Evolution, and love the historical weather feature. I don't know what I would do without it, since all my flights never use live weather as I like to mimic the weather found in the real world flights I replicate from Flightaware. Also, I will mimic a flight I took in on a real vacation, so this feature is particularly handy for that. For this reason, I always use use the "Force to Sim Time" box in ASE, so that ASE always automatically fetches the historical weather for my flights that happen using dates/times in the past. Basically, I don't need to choose the date and time in the separate Historical weather screen, as just clicking that checkbox does all the work for me.

 

However, I fear there may be price to pay for that convenience. I remember reading somewhere in this forum that the data stored on the server used for historical weather is actually "off" by a half hour or more, and that if one really wants the weather to be accurate down to the minute, it may be a better idea to manually retrieve the weather using the Historical weather screen, entering the date/time and then adding a half hour as necessary to compensate for the way the server archives weather data.

 

Is this correct? I hope I'm making sense here. I'm just looking for the maximum accuracy of weather data, as a half hour can really make a difference when it comes to the weather depiction to what I may remember from my memories of a past vacation flight.

Is the weather is right to the minute when it's live? If I understand correctly, much of the weather depiction is driven by METARs. They're a report of a snapshot. 15 minutes later they might not be right. Doesn't necessarily mean another one will be issued to replace it (unless it's operationally significant).

Any historical weather downloads will include the same METARS as if you were flying that time in real time.

If a Metar for a station was 6 hours old at the time which some in fact are, you will still get the 6 hour old METAR in the historical download.