Time arithmetic is always fun. The original ANSI SQL standard had the intelligent distinction between year-month intervals and date-time intervals for just this reason - you have to watch for errors to choose how to hand out-of-bounds conditions (e.g. "myDate + 1 units year" when myDate == 2016/03/29).

AZ is not in the Eastern Time Zone... And why are the links they're showing using the "tel:" attribute for a link address for a date? What is going on here?

AZ is mentioned as either mountain time or pacific time in the post.

I didn't notice any tel: links. And that's not the point of the article.

I see you've mentioned your points with a comment on the post itself. No need to mention it here again.

No it's not. The article explicitly says "But what if you're in Arizona? That state's on Eastern Time." And the tel: links are in the very first example listed. If they're not necessary to help with the example (and they make it much more confusing to boot), then they shouldn't be there.

I mentioned these points on the post to notify the author. I mentioned them here to add to the discussion. As you can see, the discussions in both places are different and no one has responded to the discussion on the post so I would argue that there was a need to mention it here.

But what if you’re in Arizona? That state’s on Eastern Time, and most of it doesn’t observe daylight savings.

Mountain Standard time, year-round.