Matthew,
That’s exactly why I was careful to post 2 different “explanations.” On the one hand, the actual rubrics which pastors are bound to follow; and on the other hand the part that I described as “my opinion” where I explain my own reasoning, based on the rubrics.
Should it be tailored to the location? No doubt.
Here’s where it becomes difficult to interpret the rubrics:
The Christmas Eve Vigil Mass was previously the Mass of Dec. 24 in the morning. We also had 3 Masses of Christmas: night, dawn, and day.
That’s been changed with the new Missal. The Vigil Mass has been completely moved from the morning of Dec. 24 to the evening of Dec. 24, and it is now a Mass of Christmas (no longer the last Mass of Advent).
Vigil Masses can be celebrated in the evening, or in the night. Nighttime is after all, the proper time for a vigil Mass because the word itself means “to stay awake.”
Therefore, we actually have 2 different (slightly) Masses which can be used at the same time. I don’t see a problem with that, but what I do see a difficulty determining which one to choose.
Let’s take your own situation.
At 4:30 PM, it’s dark. It is “evening” by the Church’s definition, because the time of Evening Prayer is 4 PM. Let’s remember that the English “evening” isn’t the same as the Latin “vespere” which is actually the proper and binding word. It might not be “evening” according to the secular use of the word in English, but it is “vespere” and that’s what counts.
Mass is scheduled for 4:30 PM. Which Mass to use? In my opinion, the Vigil Mass would be the appropriate text, because that’s the one that the Church says is to be used in the evening. I think that’s the best choice. However, if a priest were to look out and say that because it’s completely dark outside, and it’s truly nighttime (by the sun), therefore he uses the night Mass—I would not see any problem with that.
The Missal does say that the priest is obligated to use the Mass texts at the proper time. So we ask ourselves “what is the purpose of that rubric?” I don’t see it as being so specific that we become pharisaic about it; like saying that the dawn Mass must be precisely at sunrise. Instead, I see it as a corrective rubric to tell the priest that he may not follow the previous practice of having 3 Masses, one immediately after the other, and completely disregard the time of day. To be more direct, the priest cannot use the “Mass at dawn” if the time is 1:00 AM; nor can he use the “Mass of night” at 10:00 AM, even if it would be his first Mass of the day. In addition to night/dawn/day, the old Missal also called them the 1st Mass, 2nd Mass and 3rd Mass. From what understand, it was the practice for priests to use these 3 Masses on Christmas and do them in order, but not necessarily follow the descriptions (night, etc). So one priest might have a 9 AM Mass (night) with a congregation and then immediately say 2 more private Masses. As I see things, I believe that’s what the Church is trying to get away from (and has probably already achieved, in reality).