a '{kind}' decomposition column needs a declared integer 'period' of at least 2 (the season length - 7 for a weekly cycle in daily data, say); there is no auto-detection, so it reported null until a period is set.

Warnings reference › grid.ts.period:*:*

Identifier

grid.ts.period:*:*

Raised by

The grid (core)

Since

1.30.0

What happened

A seasonal decomposition separates a series into trend, season and remainder, and the season length has to be stated: the grid does not guess it. Without a period of at least 2 the column reports null for every row.

The fix

Declare the period in observations - 7 for a weekly cycle in daily data, 12 for a yearly cycle in monthly data.

Reference

Covered in full at the API reference.