Observance of holidays is a very character-specific trait. Some people go absolutely gaga over Christmas, while for others its more a case of "ah, crap, its that time again already, better buy some gifts before the shops become a nightmare". Here in Australia, Halloween isn't of much note at all (to my dissapointment, I never got a chance to go trick-or-treating as a kid, though I had friends who made a half-arsed effort of it), although the ever-increasing influence of the States in our culture and media means its become a more celebrated event. Valentine's Day is a big thing for couples, but much less so for single people. Easter has significance for the religious, for kids and their parents, and those who love chocolate and/or public holidays; others pay no real attention to it at all.
Age, upbringing, religion (or lack-thereof) and place of residence all play an enormous part in which holidays capture our notice and which don't.
Regardless, if nothing plot or character-relevant happens during those holidays, there's no reason whatsoever why you should need to bring them up. These are events that happen every year, at (more or less) the same time each year - in a contemporary setting, its a given that Christmas would have happened on December 26, Halloween on October 31, the 4th of July on, well, that date. Readers can assume for themselves that your character was present for them in some capacity.
But you can always slip in a mention if you want to. Often holidays and other yearly events can be an effective way to summarise the passage of time. Something like "Halloween passed without John hearing any news, and by the time Christmas and New Years had been and gone, he began to have serious concerns about Carrie's whereabouts. It wasn't until late Febuary, two weeks before his birthday, that he... etc, etc"
There's no right answer here. But if you are only mentioning these holidays because you feel you have to, then it almost certainly isn't needed.