Most of the major elections occur in November. Many government workers have three weeks off of work for Thanksgiving, Christmas, and New Years. During that time the winning candidate and the incumbent coordinate transitioning into and out of office. This also gives the new administrative staff time to prepare and get up to speed.

Kinda stupid to do it during the holidays. I also think campaigns are far too long. Losing our privacy should mean any person seeking office has at least a ten year resume on the type of person they are and who is backing them. Especially now that there is a massive trove of data, once released, with tons of people who should never have power over anyone again.