Three days and an hour more than you think, because it's the weekend, and an extra day because the public holiday for tomorrow may or not be a working day. Oh and there was a timezone change.
Even before the rollover it get's bad. I had a CI failure on 31 December 2018 for code which worked fine on 31 December 2017, because it was the first time for that code to have Dec 31 in week 1 of the next year.
And last year someone else's code failed on 30 December 2019, so I had a pretty good idea where to look.
Still need to fix a bug in code written only yesteryear because the 1st of July wasn't on a Monday this year, but I decided to snooze that test failure ... it'll work fine again in 9 years.