Are Dst index given in train data average for last hour or exact value for hour end?

Hi!
I don’t understand from the description are Dst index given in train data average for last hour or exact value for hour end? I think it’s exact value, but not sure about it. Please help to understand why it’s exact value or why it’s average… Maybe I missed some information in problem description…

Hi @personnon! Thanks for the question. Dst is officially calculated as an average value of the horizontal component of the magnetic field observed at four near-equatorial observatories. The time tags of Dst values are defined this way: The values at 00:00UT are mean of magnetic values observed between 00:00UT and 01:00UT, at 01:00UT are mean of magnetic values observed between 01:00UT and 02:00UT etc.

In short, the Dst index is the average over the next hour. Here’s a page that describes the derivation of the Dst index in more detail: http://wdc.kugi.kyoto-u.ac.jp/dstdir/dst2/onDstindex.html

Hopefully that helps!

Thank you very much for the quick and detailed answer!