(13 Months)
Evolution Va
Frank.  Leav
lly.  Jean &
e Fri. night.
          Dec. 29
Dec. 30
7 proposed holidays are typed in blue.

To convert dates from the Gregorian calendar to the Kluznickian calendar, click
To download an Excel program to do this and to get the Gregorian DOW, click

  • Simplicity, order, and regularity.
  • It is a geocentric civil calendar, not a religious or business calendar.
  • Contains no religious impositions.  (No one has the right to impose their religious
    beliefs, customs, or habits on anyone else.  See p.s. #5.)
  • Contains no business impositions.  (See p.s. #1)
  • Contains no other special interest group impositions.
  • It is a perpetual calendar, identically the same every year except leap years.
  • 13 months per year; 4 weeks per month; 7 days per week except the last week of
    December which normally has 8 days but will have 9 days on leap years.
  • Monday is the first day of each week, month, and year.
  • Leapday is the last day of the year which leaves the preceding 365 days unaffected
    and invariant from year to year.
  • Each date on the calendar will always reoccur on the same day of the week.
  • Since Monday is the 1st day of the week, both weekend days will be at the end of
    the week, side by side, both on the same row, as shown in the following monthly
  • Lastday and Leapday are a part of an extended weekend and not a part of the work
  • The winter solstice shall always occur within +/- 1 day of 1 January.  Leap days will
    be added or omitted accordingly.
  • An improved leap year rule, based on the mean solar year, is to be occasionally
    updated, when needed.  
  • The century number shall be contained within the year number, e.g. 2010 is a part
    of the 20th century, not the 21st.  (See p.s. #4)
  • The winter and summer solstice and the spring and fall equinox are proposed to be
    national holidays along with Presidents, Memorial, and Independence days, in the USA.
    (See p.s. #3)
Monthly Calendar

Month:  Any                                                                                                   Year:  Any
Calendar Reform - The Kluznickian Calendar
Yearly Calendar,   Features,   Monthly Calendar,   Discussion,   Links,   Downloads
2005 June 1                                               
Revised 2008-4-21

                                                     The Kluznickian Calendar
                                                        (A 13 Month Calendar)
                                                             by Nick Kluznick

I bought an introduction-to-astronomy book and in the chapter three homework assignment it said to
design your own calendar.  So I did, as follows.

The mean solar year consists of 365.24219 mean solar days and the lunar phase-month is 29.5306
days.  It would be nice to have the months equal one lunar phase cycle, i.e. have the new moon occur
on the first day of the month each month, but its 29.5306 day phase period is just not compatible with
365.24219 days in a solar year.  (365.24219 days per year / 29.5306 days per month = 12.368
months per year. )  If we keep 12 months per year, the days per month vary from month to month as
you know, and yet the date of the new moon still wanders through our calendar and is different month
to month and year to year.  So, since the solar year with its solar seasons is far more important than
the lunar month, forget the moon, let it wander, we shall stay with a solar calendar.  

But we can achieve a degree of regularity if we have 13 months a year, then all months will have 28
days except December, which will normally have 29 days but will also have a 30th day on leap years.  
Notice that this is 4 seven-day weeks in each month except for the end of December.  Isn't that tidy!  
And we can keep 7 day weeks.  What else can we tidy up?

Obviously the winter solstice (the longest night of the year) must be the start of the new year.  Nothing
else makes sense.  (Perihelion, currently on 2 January, doesn't do anything for me since, unlike the
solstice, its occurrence is neither obvious nor as significant.  (Axis tilt trumps orbital eccentricity.))  So,
let us realign the calendar to the 4 cardinal points of the solar year by moving the winter solstice 11
days, from December 21 to January 1.  This causes the summer solstice (the longest daylight of the
year) to fall in the middle of the 7th month, which we could call Aten (i.e.: … June, Aten, July …), or
the 15th of Aten (Egyptian sun god).  The spring (vernal) equinox (daylight hours = nighttime hours)
will fall on the 8th of April and the fall (autumnal) equinox will fall on or about the 22nd of September.  
(See p.s. #3 for a further discussion.)

Let us also declare that the 1st of January shall always be a Monday.  This means that the first of
every month will always be a Monday and the last of every month will be a Sunday except in
December, which normally has 29 days.  This 29th day of December I now call Lastday (because it is
the last day of the normal year and the last day of the normal month of December), (ie … Saturday,
Sunday, Lastday, Monday…).  Note that Lastday and Leapday (explained later) are extended
weekend days and not a part of the workweek.  Also note that Leapday is at the very end of the year
which leaves the preceding 365 days unaffected and invariant from year to year.  These
arrangements result in each date on the calendar having the same day of the week every year.  

Let us also declare that the first day of the week is Monday, and have both weekend days appear side
by side at the end of the week.  Otherwise we cannot call them the weekend days.  (Any calendar
reform proposal that does not include this feature, is unacceptable.)  In fact, we should incorporate
this feature into our calendar right now, starting next year!  It's the international standard, ISO 8601.

Tidy, tidy, tidy.  An unprecedented degree of simplicity, order and regularity.  I think it is time for
calendar reform.  But can't you just hear the Troglodytes starting to wail?  (Troglodytes are primitive
cavemen who are narrow minded, superstitious, and conservative "old dogs" (who cant or wont handle
change); akin to Luddites, who are opposed to new technology.)  

Now let us address the leap-year days.  The question is: What do we have to do to keep the winter
solstice falling on or about 1 January?  There are presently 365.24219 mean solar days per mean
solar year (MSY) so, since our calendar has only 365 days per year, in 4 years there will be an error
of 4 X 0.24219 = 0.96876 days too few.  So every 4 years we add a leap day on December 30 and
call it Leapday.  (The following day will be Monday, January 1st.)  

However, one whole day is too much as we only needed to add 0.96876 days, so there is an error of 1
– 0.96876 = 0.03124 error days every 4 years or 0.00781 error days per year.  The reciprocal of this
is 128.041 years per error day, i.e. it will take 128.041 years for this error to be one day.  So, every
128 years we will have an "omitted leap year" and need to omit that Leapday, to bring the calendar
back into alignment with the winter solstice.  

Now, 0.00781 error-days/year X 128 years = 0.99968 days of error to be corrected.  If we subtract 1
day it will be too much by 1 – 0.99968 = 0.00032 days, so somewhere down the line we will have to
add back a day to compensate for that.  (0.00032 error-days) / (128 years) = 0.00000250 error-
days/year, or 400,000 years/error-day.  Then every 400 thousand years we will have to add a
Leapday to December to regain alignment, and then it will be just about perfect again, except for two
things: a) there will be a -42.6 minute change in the MSY during that 400,000 year period, and b) the
leap year rule (LYR) will have been changed many times by then.  So forget the 400,000 year leap

    {The Gregorian LYR is: "All years that are multiples of 4 will be leap years except century years
    (the 20th century-year was 2000 AD).  Century years will be non leap years except those that are
    multiples of 400."  The comparable Kluznickian calendar LYR is: "All years that are multiples of 4
    will be leap years except those that are also multiples of 128."  Note that this rule is simple, its
    derivation is easy to understand, and it is easy to update as will be shown below.  The two rules
    are not identical.  In 4000 years the Gregorian calendar will have 4000/4 – 4000/100 + 4000/400
    = 970 leap years.  Whereas the Kluznickian calendar will have 4000/4 4000/128 = 968.75 leap
    years in 4000 years.  Therefore, the Gregorian calendar will have 1.25 days too many per 4000
    years compared to the Kluznickian calendar.  This, plus the fact that the MSY length is getting
    shorter as explained in the next paragraph, means that the Kluznickian calendar is more accurate
    than the Gregorian calendar.   NK 2008-2-17}  {This improved LYR could be implemented today,
    if the world so desired.  I recommend that we do that.   NK 2011-12-3}

    {All LYRs must be updated periodically or else eventually the winter solstice will occur when the
    calendar says it is summer time.  Why?  Primarily because the moon causes tides, which cause
    drag, which slows the spin rate of the earth, which lengthens the day, which decreases the
    number of days per year.  As the number of days per MSY decreases, the Kluznickian LYR can
    be easily updated by changing the secondary correction period of 128 years, in increments of 4
    years, thereby retaining the LYR format.  (Or it could be changed in increments of 1 or multiples
    of 1 or 4, if desired.)  For example, the decreasing length of the MSY requires that the frequency
    of occurrence of the omitted leap years be increased from time to time.  The first possible 4 year
    correction would be to change 128 years to 124 years.  (This corresponds to a -21.76 second
    change in the MSY, in about 2,000 years from now.)  The new LYR would then be: "All years that
    are multiples of 4 will be leap years except those that are also multiples of 124."
    The length of the MSY is currently decreasing at the rate of roughly 1 minute per 6,000
    years, or 1 second per 100 years, as can be derived from the charts provided by Irv
    Bromberg on his web page at .
    When looking at the Bromberg charts, notice that:
  • The MSY = the average of the lengths of the North Solstice year, the South
    Solstice year, the Northward Equinoctial year, and the Southward Equinoctial
  • The solstice and equinox year lengths oscillate about the track of the MSY length.
  • The track of the MSY length oscillates about the track of the "Mean Orbital Year"
    (MOY) length.    
  • The amplitudes of the oscillations of both the seasonal year lengths and the MSY
    length are modulated by longer period components due to phenomena such as
    the variations of the earths orbital parameters.  
  • The MOY length presently decreases at a constant rate of about 1 minute per
    9,346 years.
  • The MSY length decreases at a variable rate that is presently about 1 minute per
    6,000 years.  
    The present rough rate of -1 minute per 6,000 years will become less and less negative (ie,
    the time between LYR changes will become longer and longer) as time goes on until about
    30,000 years from now, and then it will start to become more negative again.  By the way,
    we will start using 5 years (instead of 4) for the LYR primary correction period in about
    200,000 AD.  Also, the length of the year will eventually become 364 days, in about 13.5
    million years (based on the current rate of change of the MOY).  Won't that be convenient.    
       NK 2008-3-1}

    {By continually updating the LYR (say every (1 to 10) thousand years or so) as shown above, the
    calendar can be made to track the MSY length as it slowly changes.  This can be done in such a
    way that all of the solstices and equinoxes will always occur less than +/- 1 day from their  
    celebration dates.  I recommend that our future cousins do just that.  When the calendar is on
    track with the MSY, the deviations of each pair of solstice and equinox occurrence dates, from
    the calendar as-celebrated dates, will be of equal magnitude and thus minimal, and the
    deviations will be less than +/- 1 day.   NK 2008-4-18}


p.s. #1, 2005 June 22:

Since writing the above, I found a web site dedicated to calendar reform:        
In it, it says that a French philosopher named Auguste Comte beat me to the idea of a 13 month
calendar by about 150 years.  Well rats!  There goes the Nobel Prize for Calendars.  But I still like
mine better.  His is a religious calendar, Positivist's Religion of Humanity, that is all cluttered up with
saint's names, while mine is a simple more familiar geocentric civil calendar.  (He also has a
philosophers version of the calendar that is all cluttered up with the names of philosophers and other
prominent people.)  Furthermore, he does not: a) move the winter solstice to Monday January 1, b)
use an improved leap year rule, and c) address the century number problem (see p.s. #4).  

Also mentioned is the 12 month "World Calendar" and the work leading up to it.  Its good reading.  
Check it out.  It looks like it is the leading contender for calendar reform, instead of a 13 month
calendar, because the business men of the world wanted a calendar with the number of months
divisible by 4 to make life easy for them to know when business quarters start and end.  Can you
imagine that?  They shot down a far superior 13 month calendar in order to make life a little bit easier
for the business men.  How utterly ridiculous...  It's not sufficient that there are the same number of
weeks (13) per quarter in both calendars, and it's not sufficient to tell them the start date of each
quarter (actually, in my calendar, the start of each quarter occurs on a Monday on the day of a solstice
or equinox and lasts for 3 months and 1 week), no, they want it to be in whole months.  I guess
business men can't read calendars by days or weeks, just months.  So the tail wags the dog.   This
calendar also does not start the year on the winter solstice nor does it start each year, month and
week on a Monday.  It is not as orderly as mine but I could live with it if they started the week on
Monday.  Mine is still better.

    {Each business is free to choose any quarter start-dates it likes.  And they don't all have to be the
    same.  And they do not have to burden the rest of the world with their choices.  Moreover, the
    year has either 365 or 366 days so if you divide by 4 you do not get a whole number, you get
    either 91.25 or 91.5 days per quarter.  So, no matter what calendar you use you can not divided
    it into "perfect" quarters.  But it doesn't matter.   Why not normalize the statistics of each quarter
    on a per-day basis.   For example, instead of citing the profit for the 3rd quarter, why not cite the
    average profit per day during the third quarter?  That way it doesn't matter if the number of days
    per quarter are not exactly the same, the statistics are still comparable.  NK 2007-4-16.}

p.s. #2, 2005-9-15 - DELETED

p.s. #3, 2006 March 21:

Irv Bromberg and Karl Palmen wrote to me and told me that the first day of the seasons, i.e. the
solstices and equinoxes, will not occur on the same date each year.  Holy smokes!  Who ever heard of
such a thing?  Not my introduction-to-astronomy book.  Well – lots of astronomers, as it turns out.  
Check out Irv's excellent web site
for an explanation.  Even after insuring that the winter solstice occurs on or about 1 January each
year, the start dates of the other seasons could vary from +/- 1 day to as much as +/- 2.6 days over
the millennia, depending on the type of year the leap year rule is based on and how often it is updated
throughout time.  The significance here is that we can't have fixed dates to celebrate their occurrence,
or can we?  Right now we, the USA, have holidays whose celebration dates have been moved to the
nearest Monday in order to have 3 day weekends.  That is exactly what I propose we do with the
solstices and equinoxes – celebrate them on the nominal dates shown on the calendar at the
beginning of this article.  I really like the idea of celebrating the changes of the seasons.  It is the
ecologically correct thing to do.  It makes us all more aware of the natural rhythms of the world and
also the changing nature of the world.   It gets us more down to earth, more attuned to life's cycles,
closer to mother nature.  The world doesn't stay the same; its changing all the time, short term and
long term.  We should remain aware of this by celebrating the changing of the seasons.  (See
Evolution History -
Foreword and - World for a further discussion of the changes the world undergoes.)

I have been on the www again and found out that others have stolen most of my new ideas, years
ago.  Someone already thought of declaring that the 1st of January would always be a certain day,
like Sunday or Monday.  Another already thought of starting the week with Monday in order to have
the weekend days side by side at the end of the week. I haven’t read that someone else put both
"extra" days at the very end of the year but it wouldn't surprise me if someone already did.  (There's a
lot I haven’t read.)  That doesn't leave me very much that is original –
    a) The winter solstice will always occur on or about 1 January.  (The Abysmal calendar does too.)
    b) The use of an improved leap year rule.
    c)  Correction of the century number determination.  (See p.s. #4 below.)
    d) Business quarters, school terms, and the psyches of the population in general will be aligned
    to the earth's seasons by making the solstices and equinoxes holidays.
    e) The Kluznickian calendar brings it all together: a high degree of simplicity, order and regularity,
    a geocentric civil calendar, no religious impositions, no accountant impositions, a perpetual
    calendar, 13 months per year, 4 weeks per month, 7 days per week except the last week of
    December, each week, month and year starts on a Monday, both weekend days are at the end of
    the week, Leapday is at the very end of the year so that the preceding 365 days are unaffected
    and invariant, each date on the calendar will occur on the same day of the week every year,
    Lastday and Leapday are a part of an extended weekend and not a part of the work week,
    century number correction, the winter solstice will always occur on or about 1 January, and the
    calendar will remain aligned to the length of the mean solar year by the use of an improved leap
    year rule that is to be updated as needed.

    {We could start the new year, i.e. 1 January, on the first day of spring, the vernal equinox - the
    time for new life, the time for renewal, the time for a new beginning (if you live in the northern
    hemisphere).  Well hell, that would be a hard sell to the people of the southern hemisphere.  I
    guess we are better off leaving the New Year to start on the day of the winter solstice; the
    southerners as well as the northerners will be more familiar with this.  NK 2006-10-9}  

p.s. #4, 2006 Dec 1

One more thing we should do is tidy up is the century number.  It has always bugged me that the
century number is not included in the year number.  For example, 2006 is said to be in the 21st
century.  Dumb, dumb, dumb.  It should be in the 20th century!  The 20th century-year was 2000 AD,
therefore the year 2000 was the starting year of the 20th century, not the last year of the 20th century
(and 2006 is the 6th year after the 20th century year).  You do not have a century until
after a hundred
years has passed.  Its just like people.  You don't say a kid is one year old until
after one year of his
life has passed.  And then he stays one year old until he reaches the end of the second year of his
life, etc., etc.  Dates falling within 000 AD to 099 AD should be referred to as being in century zero.  
Dates between 100 AD and 199 AD are a part of the 1st century, etc., etc.  

Another way to look at it is this: for the year 2006, the first 2 digits (20) are the
century number, the 3rd
digit (0) is the
decade number within the century, and the 4th digit (6) is the year number within the
decade.  All years that have 20 as their century number, are a part of the 20th century.

Look at a ruler or yard stick or meter stick, they all start at zero.  And so should our century numbering
system.  Zero is the first positive number of all of our measurement systems, except the Gregorian
calendar.  I think Gregory made a mistake there.   

    (The century notation is another tough one to deal with but it must be done.  It doesn't make
    sense to make several major changes to the calendar and then omit this sore thumb.  If the
    calendar is to be reformed, then let it be thorough and complete.    NK 2010-2-18)

ps #5,  2007-5-11

The last word:
  • A 13 month calendar makes a lot more sense than a 12 month calendar.
  • Some religious fundamentalists actually believe that God created the universe in 6 days and
    then rested on the 7th and, therefore, the 7 day week is considered to be sacrosanct.  They say
    that every week must have exactly 7 days, no more and no less, and (for some unknown reason)
    there can not be any extraneous days in between these weeks.  They also say that the last day
    of the week must be named the "Sabbath", the day of rest.  "That is the way that I think that my
    God wants you to make your civil calendar."  However, religious impositions are no longer
    tolerable.  The US Constitution and the UN have declared that religious freedom is a
    fundamental human right.  Everyone has the right to chose any religion they want, or no religion,
    but no one has the right to impose their religious beliefs, customs or habits on anyone else.  
    Requiring someone to use a religious calendar is a violation of their civil rights!
    Freedom of religion requires freedom from religion and separation of the church and the state.  
    The civil calendar is a matter of the state and, therefore, cannot be constrained by any religious
    dictum.  The civil calendar reform process must be completely devoid of any religious
    (Religious freedom and separation of the church and the state are very VERY important issues.  
    In fact, world peace cannot be achieved without them.  Please read Religion, parts 1 and 2.)    
  • Business impositions are completely unnecessary.  Each businesses can choose any quarter
    start dates they want without imposing them on the rest of the world, no matter what civil
    calendar is used.    
  • Calendar reform is a matter of science and common sense, not religion, not business, and
    especially not politics with their political blocs (like religious blocs), and lobbies (like business
    lobbies).  Politicians are driven by the desire to be reelected by their constituency, and that
    includes religious fundamentalists and business men...  They have a self serving hidden agenda,
    a conflict of interest!  As do the fundamentalists and the business men.  
  • The names Aten and Lastday are not carved in stone.  Aten could be Ra or Sol?  Lastday could
    be Endday?  Or how about Saint Nicholas Day, or just Nicksday?  What do you suggest?   
  • One thing we should do immediately is to make Monday the first day of the week on our civil
    calendar.  The next easiest thing to do is to get world approval to use the improved leap year
    rule, and then to declare that from "this" day forward the century number is a part of the year
    number.  Getting world approval for the rest of the Kluznickian calendar will be a much tougher
    thing to do.  

    Contact me at


Or search
13 month calendar reform.
Or search
"calendar reform"

To convert Gregorian dates to Kluznickian dates, click HERE.


DOM - Day of month
DOW - Day of week
DST - Daylight saving
Eas - Easter
FE - Fall equinox
fm - Full moon, 2005
GHD - Groundhog day
Hal - Halloween
Inde - Independence
JC - Jesus Christ day?
Labr - Labor day
Me - My birthday
Mem - Memorial day
MLK - M L King day
Mom - Mothers day
nm - New moon, 2005
NYE - New year eve
Pat - St Pat's day
Pres - Presidents day
SE - Spring equinox
SS - Summer solstice
TGD  - Thanks day
Val - Valentines day
Vets - Veterans day
WS - Winter solstice
Yule - New Xmas?
1492 - Columbus day
Original: 2005-6-1
Revised: 2008-4-21
Last amended: 2017-1-24
With Saturday and
Sunday side by side,
you can write in a
end trip right
across both of them like:
"Evolution Vally. Jean &
Frank.  Leave Fri. night."
Try doing that when the
week starts on Sunday!