# Why does the first day of the month fall when it does? **URL:** \ **Category:** Factual Questions\ **Created:** [August 31, 2000, 6:45pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526 "2000-08-31T18:45:29Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![dougie\_monty](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@dougie\_monty](https://boards.straightdope.com/u/dougie_monty)\ **Post date:** [August 31, 2000, 6:45pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/1 "2000-08-31T18:45:29Z")
Isn’t it strange that the seasons begin around the 20th to the 22nd of March, June, September, and December, instead of around the first? How did this happen? I also understand that, originally, the Roman civil year (at least) began on March 25, and there was some stigma attached to January 1 as New Year’s Day. Why? For the same reason, the astrological signs change around the third week of the month, year round. Was this an effort of the Catholic Church–or the people who worked out the Gregorian Calendar–to distance the first of the month from astrology? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 31, 2000, 6:56pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/2 "2000-08-31T18:56:01Z")
The astrological signs correspond roughly to certain constellations in the sky, and the month of a “sign” is the time period when the Sun passes through that constellation. Approximately. There’s three complicating factors: First, the Sun passes through thirteen constellations, not twelve. Since thirteen is an unlucky number, astrologers ignore Ophiochus. Secondly, the constellations are not all the same size, so the Sun doesn’t spend the same amount of time in each, so they just sort of average them out to a twelfth of a year each. Thirdly, the dates were all set several thousand years ago, and thanks to something called precession, they’re all about a month off. The point is, though, that the definition of the Zodiacal signs is completely independent of the calander months. As for the months being offset from the equinoxes/solstices, I don’t know all the details, but it’s mostly a matter of ancient Roman politics. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [August 31, 2000, 7:39pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/3 "2000-08-31T19:39:22Z")
This might shed some light on it, but maybe not. I’ve referred to it a number of times: [http://www.pauahtun.org/CalendarFAQ/cal/calendar22.txt](http://www.pauahtun.org/CalendarFAQ/cal/calendar22.txt) ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [August 31, 2000, 9:50pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/4 "2000-08-31T21:50:08Z")
To answer your first question, it’s a myth that seasons start on the soltices/equinoxes. There is no “official” start to the seasons, but they traditionally were considered to start March 1, June 1, September 1, and December 1. TV weather forecasters have been spreading this lie for some time. The master wrote this: [Is it true summer in Ireland starts May 1?](http://www.straightdope.com/classics/a1_170b.html) ---
**Author:** ![Phobos](https://avatars.discourse-cdn.com/v4/letter/p/3d9bf3/32.png) [@Phobos](https://boards.straightdope.com/u/Phobos)\ **Post date:** [August 31, 2000, 10:18pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/5 "2000-08-31T22:18:18Z")
> [@](#): > > \*Originally posted by Chronos \* > \*\*the Sun passes through thirteen constellations, not twelve. \*\* and the planets pass through even more than that! ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [August 31, 2000, 11:21pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/6 "2000-08-31T23:21:42Z")
\>\> it’s a myth that seasons start on the soltices/equinoxes I would not call it myth. It is just a matter of definition. this is like arguing whether the tomato is a fruit. The solstices and equinoxes make good time marks but you can have your own definition for the seasons. ---
**Author:** ![Olentzero](https://avatars.discourse-cdn.com/v4/letter/o/90ced4/32.png) [@Olentzero](https://boards.straightdope.com/u/Olentzero)\ **Post date:** [September 1, 2000, 5:40pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/7 "2000-09-01T17:40:12Z")
> [@](#): > > _Originally posted by Chronos \* > \*\* First, the Sun passes through thirteen constellations, not twelve._\* Actually, no. According to my handy dandy _Uranometria 2000.0_\*, the path of the ecliptic passes through 14 constellations - the Sun spends a day or two in a tiny corner of the constellation Cetus. Places like Stonehenge, IMO, indicate that ancient civilizations attached a lot of importance to the equinoces and the solstices, and considered them the beginning of the seasons. I would think that precession kinda knocked things out of whack, so that the dates on which the equinoces and solstices fall are creeping backwards up the calendar. This is all just a WAG, to be sure, but it does make some sense to me. Anyone with better knowledge of the effects of precession? ---
**Author:** ![Olentzero](https://avatars.discourse-cdn.com/v4/letter/o/90ced4/32.png) [@Olentzero](https://boards.straightdope.com/u/Olentzero)\ **Post date:** [September 1, 2000, 6:09pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/8 "2000-09-01T18:09:37Z")
OK, from [this](http://csep10.phys.utk.edu/astr161/lect/time/precession.html) site: > [@](#): > > **Because of the precession of the equinoxes, the vernal equinox moves through all the constellations of the Zodiac over the 26,000 year precession period. Presently the vernal equinox is in the constellation Pisces and is slowly approaching Aquarius.** So eventually, in another 2,000 years, the horoscopes will be two constellations off, instead of one. But will the equinox still be on March 21st at that time? [This](http://www.treasure-troves.com/astro/VernalEquinox.html) site, although it only gives a 400-year span, does seem to indicate it is indeed moving backwards and will come earlier in March as the years progress. So, ultimately, my guess is still that the first of the month (April, in this case) and the vernal equinox coincided at some point in human history, but given the fact that the Universe isn’t exactly the most mathematical of machines, we get the current situation. Which actually kinda makes it much more interesting. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [September 1, 2000, 7:14pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/9 "2000-09-01T19:14:13Z")
The equinox will not move because that is how we have defined the calendar. A (tropical) year is _defined_ as the amount of time between two consecutive Spring equinoxes. To have the equinox move would be a contradiction of the definition. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [September 1, 2000, 7:31pm UTC](https://boards.straightdope.com/t/why-does-the-first-day-of-the-month-fall-when-it-does/31526/10 "2000-09-01T19:31:01Z")
Regarding the positioning of equinox’es: When Gregory reformed the calendar in 1582, he corrected to get the equinoxes back to around the 21st where they “belonged” (by 1582 on the Julian calendar, they had slipped back to around the 10th or 11th). He thought they “belonged” there because that was consistent with observations made by church astronomers in the early part of the 4th century. As observed, the postioning with respect to the calendar is arbitrary. Those 4th century observations on the Julian calendar just happen to be the baseline Gregory (or his underlings who actually did the work) bequeathed to us.