Tag Archive | leap year

Error In MS Excel 2016 — Treats ‘1900’ As A Leap Year, And It Was NOT!

by Anura Guruge


Click picture to ENLARGE.


IF you really were a Year 2000 aficionado and followed all of the Y2K drama you would know that all centurial years are NOT Leap Years.

For centurial years it is NOT enough to be divisible just by 4. It also has to be divisible by 400. This is was another major improvement to the Gregorian calendar to keep the year lengths as close to 365.242199 days as possible.

So, 1700, 1800, 1900 were NOT LEAP YEARS since they are NOT divisible by 400.

But, 2000 was, because it is divisible by 400.

Excel has 1900 as a LEAP YEAR.

Yes, I am probably the ONLY one in the whole world that would NOTICE and CARE.

But, I do a LOT of date span calculations — example when I am working out ICE-OUTS for lakes. In such calculations, being the pedant I am, I take into account Leap Years. Otherwise you are mistating some date spans.

That is how I noticed.

You can check it out.


Related posts:
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by Anura Guruge

Lake Winnipesaukee 2018 Ice-Out — Latest Since 2001 & ANOTHER On A Thursday!

by Anura Guruge


Click to ENLARGE. The ebb and flow of ice-out dates 1988 to 2018.


Click to ENLARGE. Other ice-outs 115 days in. All on NON-Leap Years (and ‘1900’ was NOT a Leap Year). 4 on a Thursday.


Click to ENLARGE. Ice-out dates 1990 to 2018.


So Winnipesaukee ice-out 2018 was on Thursday, April 26 around 5:40pm.

> >  This was the LATEST ice-out since 2001 when the ice-out was on May 2 (and I remember that).

> >  Another ice-out on a Thursday. We have had more ice-outs on Thursday than any other day, BY FAR.

> >  Last time ice-out was on April 26 was in 1979, 39-years ago.

> >  All ice-outs that have happened 115-days into the year have happened on NON-LEAP Years, so all are on April 26. [115-days in on a Leap-Year would be April 25.]

> >  The average for ice-out was (and still is after this year) 108.2 days in; i.e., April 19 (non-Leap) & April 18 (Leap).

> >  Ice-out in 2003 was on April 25 (114 days). Ice-out in 2008 & 2015 was 113-days in (April 23 & April 24 because one was a Leap).

> >  Ice-outs in 2016, 2012 & 2010 were way below average.


Related posts:
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by Anura Guruge


Lake Winnipesaukee [NH] 2017 Ice-Out Occurs On Monday, April 17 — As Predicted.

by Anura Guruge



Click to ENLARGE and study here. My spreadsheet takes into account LEAP YEARS and determines ice-out in terms of days into the year as of January 1 of that year.


So Winnipesaukee ice-out 2017 did take place on Monday, April 17, as was predicted here yesterday.

So it was the DAY AFTER Easter.

Same day it happened in 2013. So nothing too remarkable.

The AVERAGE ice-out is still between April 18 & April 19, so April 17 is v. close to average.

It has fallen on April 17 six times before — as of 1887.

You can see that above.

But, I factor in whether it was a LEAP-YEAR of not.

That makes a difference.

April 17 is 106 days into the year in non-Leap Years. 2017 is NOT a Leap-Year.


Related posts:
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by Anura Guruge


Lake Winnipesaukee, NH Ice-Out 2017 Could Be On Monday, April 17.

by Anura Guruge


Click to ENLARGE and study here. My spreadsheet takes into account LEAP YEARS and determines ice-out in terms of days into the year as of January 1 of that year.


So the informed consensus is that the 2017 Winnipesaukee ice-out will most likely happen on Monday, April 17th — the DAY AFTER Easter.

The AVERAGE ice-out is still between April 18 & April 19, so April 17 is v. close to average.

It has fallen on April 17 six times before — as of 1887.

You can see that above.

But, I factor in whether it was a LEAP-YEAR of not.

That makes a difference.

April 17 is 106 days into the year in non-Leap Years. 2017 is NOT a Leap-Year.

So if it happens April 17, 2017 it will be on Day 106 into 2017.

So the last time it happened as such was just 4 years ago, 2013.


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by Anura Guruge


Lake Winnipesaukee, NH Ice-Out 2016 — Ice-Out BEFORE Easter Is Not That Unusual.

by Anura Guruge


The RECORD
2016 Lake Winnipesaukee Ice-Out,
declared Friday, March 18, 2016,
77 Days into the Year
(while prior record was 82 days).

See this post for all the statistics.

Some have commented that 2016 Ice-Out is before Easter
— 2016 Easter on Sunday, March 27.

This, however, is not that unusual given that
Easter can occur as late as April 25.

27 instances of Ice-Out before Easter
(counting 2016) AND 4 cases when
Ice-Out was ON Easter.

That means that in the 130 years that we have records for,
Ice-Out happened on/before Easter 24% of the time.


iceoutbeforeeaster111

Click to ENLARGE.


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by Anura Guruge


Lake Winnipesaukee, NH Ice-Out 2016 — Friday, March 18; Breaks Old Record By 5 Full Days.

by Anura Guruge


2016 Lake Winnipesaukee Ice-Out was declared
just before noon on

Friday, March 18, 2016.

77 Days into the year.

Previous (known record), 2010 & 2012, was 82 days in.

Remember Leap Years bring in the dates, post February 29, by one.
So both March 23 & 24 are 82 days into the year depending on Leap Year.


iceout2016wmur

From WMUR. Click to access.



Click on images BELOW to ENLARGE.



Beats 2010 & 2012 Record by 5 full days.

iceout2016earliest


Coincidentally, and very coincidentally, 2016 & 2015 ice-outs both on a Friday.

Most have occurred on Thursdays.

iceoutdayofweek


Lake Winnipesaukee Ice-Out Dates for the last 25 years.

You can’t really claim there is a trend at present.

iceoutlast25years
iceoutlast25yearsgraph


Now the other end. The Latest Ice-Outs Ever.

iceoutlongest


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by Anura Guruge


Lake Winnipesaukee, NH: Ice-Out For Last 25 Years. Record = 2010 & 2012.

by Anura Guruge


iceout25years
Click to ENLARGE.


I have all the dates going back to 1887 — 129 years. Average during that time is April 19 (depending on Leap Years).

But I thought 25 years was a good window.

So BOTH all time records have been in within the last 7 years!

But, please, let us not take this as a definitive sign of Global Warming. Last year and year before we had ice outs close to average.

I am sure that this year, 2016, ice out will set a new record.


Sunday, March 13, 2016, 2pm,
Alton Bay. [Click to ENLARGE]

P1000497


Related posts:
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by Anura Guruge


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