Washington DC federal worker here. It is expected that for a meeting some fair percentage of the attendees will drift in between 1 and 5 minutes late, and it’s not really an issue. 5 - 10 minutes late requires a mumbled apology. More than that and you were definitely late.
I think DC culture assumes that everyone has back to back meetings all the time (I know I do), so there has to be a tiny bit of slack just for that.
Oh don’t get me started. I’m a Dutch person living in Italy who is often being called ‘precise’ or even ‘anxious’ (by my south of Italy BF) for just wanting to get there on time or getting annoyed by being kept waiting by people arriving at their leisure. sigh It’s no use getting mad, but deep down I will always believe that it’s just easier and more respectful to decide on a time and arrive at that time.
Here in Israel, business stuff usually allows a 10-15 period grace period, although it depends on the circumstances and work environment. People generally understand that other people also have lives, and that it’s not always easy to fit everything so neatly on your schedule. The world doesn’t revolve around the person calling the meeting; people are busy, which means that sometimes they’ll be late.
Social events are looser. As a general rule of thumb, the larger the party, the greater the leeway. For small gatherings, half an hour is OK, and for big stuff like weddings you should show up between 15 minutes and an hour after the listed time. Note that I said 15 minutes, minimum - unless you’re close friends or family, showing up on time to a wedding is a major faux pas. My own wedding, we invited people for 19:00. By 20:00 most of the guests had arrived, and we started with the ceremony at 20:30, as planned.
Weirdly, the only social events in this country that always start *exactly *on time are funerals.
Mid-westerner here.
Being on-time matters a lot. I see it as rude when someone is frequently late.
I have an uncle that shows up an hour later for family functions. Unacceptable.
Case in point: this afternoon I heard someone getting chewed out in the hallway by her supervisor for being late to their 1pm meeting. It was 1:02.
American northwest here. As best I can tell, the rule is “we won’t yell at you for not being on time, but we also won’t wait.” I personally feel that some times matter more than others - I’ll be pretty damned punctual about work meetings and scheduled time with friends, but if I’m late for a doctor’s appointment I’ll assume they’ll not care much - they’ll either accept me when they can or will tell me to reschedule. I’m also constantly late for work, but I’m both salaried and awesome so nobody cares, so I don’t bother even trying for punctuality. And my father is seriously anal about time and also kind of a jerk about it so I have to constantly resist the temptation to be late for everything he schedules just on principle.
I’m complicated, is what I’m saying. 
I’m another Midwes person who is always early. When teaching or running meetings, I start on time and end on time. No backtracking for those who can’t get their asses in their seat on time.
The combination of serving in the military and living in the New York metropolitan area means that I care a lot about being on time.
And it causes me endless frustration when dealing with other people who take the agreed upon clock time as a mere suggestion.
I knew a boss who would always start his meetings on time by discussing staff budgets. After a few people missed their chance to defend their budget requests, his meetings always started on time! 
The best post in this thread is the one from Israel-only funerals start on time. Naturally the one meeting where an attendee has a valid excuse and no reason to use it.