A nice article that can help people understand why time series regressions techniques requires special care and why R² is an outdated concept in statistics.
A 0.97 is good for a linear regression with 2 parameters. This model has 18 parameters, that is a lot, and perhaps more if you count the freedom to chose sin, cos, sqrt, and other stuff there.
It reminds me "discovery" of phosphine in Venus, where they were using a polynomial of degree 12.
