Formal word/phrase to refer to "year begin" effect

I want to find a single word or perhaps an academic-sounding phrase to refer to the effect on something that results from the calendar year changing. I initially tried: "year begin effect" but this kind of sounds too caveman-ish.

One example sentence to frame the usage:

The ______ effect was very noticeable this year, with sales growth across multiple product categories.

Solution 1:

A recent study used the term Fresh Start Effect to describe changes in motivation caused by a temporal landmark, such as a new year, or even a new month, or a new week.

It's not too much of a stretch to use it in the context you want, which is to describe the general effect on something arising from a new calendar year

The Fresh Start Effect was very noticeable this year, with sales growth across multiple product categories.