Maybe I’m missing something but I’ve dug through the API documentation and haven’t found anything that explains exactly what these various fields are. In the sky & tempest observations, what exactly do the “Rain Accumulated Final (Rain Check)” and “Local Day Rain Accumulation Final (Rain Check) (mm)” fields represent? Under what conditions to they get updated, and also reset?
Some thoughts, but by no means a definitive answer.
I believe these fields are populated once RainCheck has been run. That will be sometime after midnight and before 8 am for stations in the continental USA. I assume for stations outside this area they will always remain at zero.
One rain check has run for a station, and you query the API for data from the previous day (i.e. the day that has just been adjusted by RainCheck) these fields should be populated.
This will give the rain accumulation values for each one minute observation period after the RainCheck correction has been applied.
This will give the total rain accumulation since midnight local time after RainCheck has been applied.
Hope this helps