Cycling UK Forum

The clock we have on the wall in the kitchen (battery driven) has a day and a date window.
The day and date change over at midnight of course, but it's not an automatic system.
This means that when there isn't a 31day month, the date is wrong the following day. The day of the week is always correct of course, so we have to move the date on manually.

Question:
Today, the clock is correct. Friday 1st.
On Monday Feb 1st it'll be correct too, as January has 31days in it.
By the time we get to Monday 1st March, the date will be shown as 29th. April, June and September will exacerbate this issue.

So .......... if we never corrected the date, when will the clock's date be correct again?

Looses 27 days every four years
365/27 gives 13.5 four year periods to loose a year
54 years is my best estimate but I think the battery will have run down before then and you won’t be around to see if I’m right.

Couple of possible answers:
* Not any time soon...
* No iDear - just check your iPhone
* irrelevent as the battery will have conked out long before it happens.
Hope that helps - and Happy New Year!

The clock only shows the day and the date (number) not the month, so when will the date number be correct again?
I very much doubt it'll 54years.

Constant 31 day months, so at a guess it'll be a couple or so years until it shows No1 on the 1st of any month again.

1st May 2025

photobike wrote:1st May 2025

Can you explain your calculation please?
Not doubting you in the slightest, but it would be nice to see how you did it.

Took 5 seconds in Excel

Placed 1-Jan-2021 in a cell. Added 31 to that and copied and pasted the formula (to get all dates that were 31 days apart). Glanced down to find the first date that started with a 1. Sequence copied here.

01-Jan-21
01-Feb-21
04-Mar-21
04-Apr-21
05-May-21
05-Jun-21
06-Jul-21
06-Aug-21
06-Sep-21
07-Oct-21
07-Nov-21
08-Dec-21
08-Jan-22
08-Feb-22
11-Mar-22
11-Apr-22
12-May-22
12-Jun-22
13-Jul-22
13-Aug-22
13-Sep-22
14-Oct-22
14-Nov-22
15-Dec-22
15-Jan-23
15-Feb-23
18-Mar-23
18-Apr-23
19-May-23
19-Jun-23
20-Jul-23
20-Aug-23
20-Sep-23
21-Oct-23
21-Nov-23
22-Dec-23
22-Jan-24
22-Feb-24
24-Mar-24
24-Apr-24
25-May-24
25-Jun-24
26-Jul-24
26-Aug-24
26-Sep-24
27-Oct-24
27-Nov-24
28-Dec-24
28-Jan-25
28-Feb-25
31-Mar-25
01-May-25
01-Jun-25
02-Jul-25
02-Aug-25
02-Sep-25
03-Oct-25

If you waited until 1st of May to stop changing it, it wouldn’t be correct again until 1st July 2030

Mick F wrote:

photobike wrote:1st May 2025

Can you explain your calculation please?
Not doubting you in the slightest, but it would be nice to see how you did it.

1st May 2025 is a Thursday but 1 Jan 2021 is a Friday. The clock and question are about both "Day" (e.g. Mon, Tues, Wed) and "Date" (e.g. 1/Jan 2021, 1/Feb/2021) being correct again.

Ian

Mick F wrote:The clock we have on the wall in the kitchen (battery driven) has a day and a date window.
The day and date change over at midnight of course, but it's not an automatic system.
This means that when there isn't a 31day month, the date is wrong the following day. The day of the week is always correct of course, so we have to move the date on manually.

Question:
Today, the clock is correct. Friday 1st.
On Monday Feb 1st it'll be correct too, as January has 31days in it.
By the time we get to Monday 1st March, the date will be shown as 29th. April, June and September will exacerbate this issue.

So .......... if we never corrected the date, when will the clock's date be correct again?

Haven't you asked this question before? Or one very similar. I think Excel was cited in at least one of the solutions then as well (other spreadsheet programs are available).

Psamathe wrote:

Mick F wrote:

photobike wrote:1st May 2025

Can you explain your calculation please?
Not doubting you in the slightest, but it would be nice to see how you did it.

1st May 2025 is a Thursday but 1 Jan 2021 is a Friday. The clock and question are about both "Day" (e.g. Mon, Tues, Wed) and "Date" (e.g. 1/Jan 2021, 1/Feb/2021) being correct again.

Ian

I’ve no particular reason to believe I’m right (or wrong)! on 1st May as it was done quickly! My understanding is that the day and date will increment independently, I understood the issue to be when will it next display correctly. Given that the day of the week is always correct, the date it would display correctly would be when the 1 is showing on 1st of the month which was what I had (back of the excel packet) calculated as 1 May 25.

Peter

sjs wrote:

Mick F wrote:The clock we have on the wall in the kitchen (battery driven) has a day and a date window.
The day and date change over at midnight of course, but it's not an automatic system.
This means that when there isn't a 31day month, the date is wrong the following day. The day of the week is always correct of course, so we have to move the date on manually.

Question:
Today, the clock is correct. Friday 1st.
On Monday Feb 1st it'll be correct too, as January has 31days in it.
By the time we get to Monday 1st March, the date will be shown as 29th. April, June and September will exacerbate this issue.

So .......... if we never corrected the date, when will the clock's date be correct again?

Haven't you asked this question before? Or one very similar. I think Excel was cited in at least one of the solutions then as well (other spreadsheet programs are available).

https://forum.cyclinguk.org/viewtopic.php?f=15&t=131885&p=1383187

Happy New Month

Jonathan

photobike wrote:

Psamathe wrote:

Mick F wrote:Can you explain your calculation please?
Not doubting you in the slightest, but it would be nice to see how you did it.

1st May 2025 is a Thursday but 1 Jan 2021 is a Friday. The clock and question are about both "Day" (e.g. Mon, Tues, Wed) and "Date" (e.g. 1/Jan 2021, 1/Feb/2021) being correct again.

Ian

I’ve no particular reason to believe I’m right (or wrong)! on 1st May as it was done quickly! My understanding is that the day and date will increment independently, I understood the issue to be when will it next display correctly. Given that the day of the week is always correct, the date it would display correctly would be when the 1 is showing on 1st of the month which was what I had (back of the excel packet) calculated as 1 May 25.

Peter

Very true. As you say, day will always be correct so my point is wrong.

Ian

Hi,
You think you've got problems

I have a mechanical watch with day, date, month and moon phase.

It sits in a watch winder when not being worn as it’s a pain to reset it all.