Hi- It it possible to account for repeated, seasonal (i.e., monthly) spikes in Amelia? It seems that the polytime or splinetime arguments can capture moderate seasonal variability, but less adept at major spikes in, for example, heating use in December and January. So far I've tried: 1) increasing the order of splinetime to make it more flexible, 2) including month as a nominal variable, and 3) including the value from the same month in the previous and next year as additional columns in each row. All of these help, but only to a minor degree. Thanks for any ideas or guidance. Mike