(Credit: E. Siegel, with a public domain conventional calendar at left) The conventional way we display annual calendars, at left, requires us to examine each month separately, either relegating the full year to a tiny font on a single page or onto 12 separate pages. Instead, the one-page calendar, at right, enables you to find whatever you want all throughout the year.
5 mins read. //
Each year, most of us throw out our old calendar and replace it with a new one. Each month, we flip our calendar forward another page, and if we ever need to know which day-of-the-week corresponds to a particular day/month combination, we have to either calculate it ourselves or flip forward/backward to the relevant month. Simple but curious questions, such as:
- What date will American Thanksgiving fall on this year?
- Which months have a “Friday, the 13th” in them?
- What day of the week does July 4th fall on?
- Or which day of the week is Christmas Day?
aren’t so easy to figure out unless you actually flip to the needed month (or look up all of the months) to figure out what the proper answer is.
But it turns out that, mathematically, the answer to these questions — or any question where you want to match up the day of the week with the day/month combination in a year — are extremely predictable, straightforward, and simple to figure out. If, that is, you don’t restrict yourself to using a conventional 12-month calendar, but rather use this one-page calendar that not only lasts the whole year, but that’s extremely easy to adjust for any/all years into the future. Let’s show you what it’s all about.
(Credit: E. Siegel) Rather than a calendar displaying separate images for each month out of the year, this one-page calendar can be used to match up the day of the week with the dates/months of the year with perfect accuracy all in a single view.
Above, you can see the 2023 iteration of a one-page calendar. On the lower-left, you can see the days of the month, which works for all months as long as you know that:
- January, March, May, July, August, October and December all have 31 days in them,
- April, June, September and November all have 30 days in them,
- and February has either 28 days (for non-leap years) or 29 days (on leap years) dependent on the year itself.
So long as you know this, it’s very easy to use this calendar to match up the day/month of the year with the day of the week that it falls on.
Examples...
Let’s go through some examples to see how to use this. First, let’s consider American Thanksgiving, which is always celebrated on the fourth Thursday of November. You’ll always know the month and the day of the week that it falls on, but the actual date — i.e., the day in November — on which it falls changes from year-to-year.
On any other calendar, you’d have to flip to November and actually see what date the fourth Thursday of the month is. But for this one-page calendar, all you need to do is:
- start at the top-right and select the month “November,”
- drag your finger down until you get to the day “Thursday,”
- and then move to the left until you get to the “fourth Thursday” on the monthly calendar.
And there, plain as day, is the answer: American Thanksgiving, the fourth Thursday of November, is the 23rd in 2023. This is the method you’d use for any known month and day-of-the-week combination you can imagine: start at the month, drag your finger down to the desired day-of-the-week, and then move to the left until you see which dates correspond to the combination in question.
What if you had a different question, though: where you knew the day of the week and the date of the month you were interested in, but you didn’t know which month(s) it applied to?
With the same one-page calendar, a different method leads you straight to the answer. For instance, which months, this year, have a “Friday the 13th” in them? To find out, simply:
(Credit: E. Siegel)I If you know which date/day-of-the-week combination you’re seeking but don’t know which months will meet that criteria, start with the date (1-31), move to the right until you find the day of the week you want, then move up and find which months match that criteria. Every year will always have at least one such combination.
Sure enough, there are two Friday the 13ths in 2023: one was earlier this month, in January, but there will indeed be another one coming up in October.
However, perhaps the most common reason to refer to a calendar is when you know what the month/day combination you’re curious about is, but you don’t know what day of the week it’s going to fall on.
This is where the one-page calendar really shines, especially as compared to other calendars that only show one month at at time. To use an example, let’s say you’re interested in the United States of America’s Independence Day: July 4th. The way you find the day of the week here is:
- start on the left on the 4th, the day of the month you know,
- also start on the top-right with July, the month of the year that you know,
- and move your two fingers, respectively, to the right and down until they meet: on a Tuesday in 2023.
And that’s it: that’s how you find the day of the week that your desired day/month combination falls on.
(Credit: E. Siegel) If you were curious as to which day of the week July 4th, 2023 fell on, rather than flipping a conventional calendar to July and seeing, you could trace “4” to the right and “July” down, finding where they meet (on a Tuesday) revealing the day-of-the-week.
Let’s pick a more globally celebrated holiday for another example: Christmas Day. Each and every year, Christmas Day falls on December 25th, but unless your conventional calendar happens to be open to December of your particular year right at this moment, a question like “What day of the week does Christmas fall on?” seems to be a very hard one to answer.
Not so with the one-page calendar!
Remember how this works: you know the day of the month, which appears on the left. You also know the month of the year, which is written on the top-right. Put two fingers, one from each hand, on the date (25th) and the month (December), and then slide the “day” hand to the right while you slide the “month” hand downward until they meet.
Lo and behold, they meet right on Monday: the day of the week that corresponds to December 25, 2023.
(Credit: E. Siegel) Using the one-page calendar for 2023, you can figure out the day-of-the-week of any calendar day by placing one finger on the “date” at left and another on the “month” at top. By moving your fingers respectively to the right and down, where they meet will reveal the day of the week to you.
That’s all well-and-good for 2023, but what happens when we move forward in time, and we switch over to the next year? Or, even more severely, what if we want to know the day-of-the-week/day/month combination many years from now?
This is where — in my opinion — the one-page calendar truly shines in its power.
The simple reason is because, except for the placement of the months (in blue) in the upper-right corner of the one-page calendar, everything else is always the same, year-after-year. Moreover, the way the months are placed shifts in an extremely predictable, repeating pattern.
You see, each non-leap year has 365 days in it: just one day more than the number of days in a full 52 weeks (which is 364). As a result, since January 1, 2023 began on a Sunday, and since 2023 has 365 days within it, we immediately know that December 31, 2023 will end on a Sunday (which you can confirm using the one-page calendar if you like), and therefore January 1, 2024 will begin on a Monday. All you have to do, then, is rearrange the placement of the months for 2024, keeping in mind that February, in 2024, will have 29 days, as it falls within a leap year.