BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Athena//Cycle calendar//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:Period windows — estimates\, not dates
X-WR-CALDESC:The next 6 periods projected from 30 August 2026 and a 28-day 
 cycle. Every entry is the window the period is likely to start in\, and th
 e windows widen the further ahead they go.
BEGIN:VEVENT
UID:cd39d43339128aba-p1@athenacycle.app
DTSTAMP:20260913T004228Z
DTSTART;VALUE=DATE:20260924
DTEND;VALUE=DATE:20261001
SUMMARY:Period likely to start in this 7-day window (estimate)
DESCRIPTION:The middle of this window is 27 September 2026. It runs 24 Sept
 ember 2026 to 30 September 2026 — 7 days wide.\n\nWorked out by adding y
 our cycle length to 30 August 2026 once\, and widening it by the shortest 
 and longest cycle you gave: 25 to 31 days.\n\nCycle 1 of 6. Each window is
  wider than the one before it\, because every cycle in between can move an
 d the movement adds up.\n\nThis block is a window\, not a date. The middle
  of it is the arithmetic\; the edges are how far the arithmetic can be out
 .\n\nCycles move. Across 612\,613 cycles the mean movement in one person's
  own cycle length was 2.6 days from one cycle to the next\, and researcher
 s working from calendar data alone concluded that predicting ovulation fro
 m it was not possible.\n\nThis is not contraception and it cannot be made 
 into contraception. Followed imperfectly\, fertility awareness is about 76
 % effective — 24 women in 100 get pregnant in a year — and the NHS doe
 s not officially recommend any app or device for it.\n\nGeneral informatio
 n\, not medical advice. When the period actually arrives\, that real date 
 is worth more than any of these.
TRANSP:TRANSPARENT
END:VEVENT
BEGIN:VEVENT
UID:cd39d43339128aba-p2@athenacycle.app
DTSTAMP:20260913T004228Z
DTSTART;VALUE=DATE:20261019
DTEND;VALUE=DATE:20261101
SUMMARY:Period likely to start in this 13-day window (estimate)
DESCRIPTION:The middle of this window is 25 October 2026. It runs 19 Octobe
 r 2026 to 31 October 2026 — 13 days wide.\n\nWorked out by adding your c
 ycle length to 30 August 2026 twice\, and widening it by the shortest and 
 longest cycle you gave: 25 to 31 days.\n\nCycle 2 of 6. Each window is wid
 er than the one before it\, because every cycle in between can move and th
 e movement adds up.\n\nThis block is a window\, not a date. The middle of 
 it is the arithmetic\; the edges are how far the arithmetic can be out.\n\
 nCycles move. Across 612\,613 cycles the mean movement in one person's own
  cycle length was 2.6 days from one cycle to the next\, and researchers wo
 rking from calendar data alone concluded that predicting ovulation from it
  was not possible.\n\nThis is not contraception and it cannot be made into
  contraception. Followed imperfectly\, fertility awareness is about 76% ef
 fective — 24 women in 100 get pregnant in a year — and the NHS does no
 t officially recommend any app or device for it.\n\nGeneral information\, 
 not medical advice. When the period actually arrives\, that real date is w
 orth more than any of these.
TRANSP:TRANSPARENT
END:VEVENT
BEGIN:VEVENT
UID:cd39d43339128aba-p3@athenacycle.app
DTSTAMP:20260913T004228Z
DTSTART;VALUE=DATE:20261113
DTEND;VALUE=DATE:20261202
SUMMARY:Period likely to start in this 19-day window (estimate)
DESCRIPTION:The middle of this window is 22 November 2026. It runs 13 Novem
 ber 2026 to 1 December 2026 — 19 days wide.\n\nWorked out by adding your
  cycle length to 30 August 2026 3 times over\, and widening it by the shor
 test and longest cycle you gave: 25 to 31 days.\n\nCycle 3 of 6. Each wind
 ow is wider than the one before it\, because every cycle in between can mo
 ve and the movement adds up.\n\nThis block is a window\, not a date. The m
 iddle of it is the arithmetic\; the edges are how far the arithmetic can b
 e out.\n\nCycles move. Across 612\,613 cycles the mean movement in one per
 son's own cycle length was 2.6 days from one cycle to the next\, and resea
 rchers working from calendar data alone concluded that predicting ovulatio
 n from it was not possible.\n\nThis is not contraception and it cannot be 
 made into contraception. Followed imperfectly\, fertility awareness is abo
 ut 76% effective — 24 women in 100 get pregnant in a year — and the NH
 S does not officially recommend any app or device for it.\n\nGeneral infor
 mation\, not medical advice. When the period actually arrives\, that real 
 date is worth more than any of these.
TRANSP:TRANSPARENT
END:VEVENT
BEGIN:VEVENT
UID:cd39d43339128aba-p4@athenacycle.app
DTSTAMP:20260913T004228Z
DTSTART;VALUE=DATE:20261208
DTEND;VALUE=DATE:20270102
SUMMARY:Period likely to start in this 25-day window (estimate)
DESCRIPTION:The middle of this window is 20 December 2026. It runs 8 Decemb
 er 2026 to 1 January 2027 — 25 days wide.\n\nWorked out by adding your c
 ycle length to 30 August 2026 4 times over\, and widening it by the shorte
 st and longest cycle you gave: 25 to 31 days.\n\nCycle 4 of 6. Each window
  is wider than the one before it\, because every cycle in between can move
  and the movement adds up.\n\nThis block is a window\, not a date. The mid
 dle of it is the arithmetic\; the edges are how far the arithmetic can be 
 out.\n\nCycles move. Across 612\,613 cycles the mean movement in one perso
 n's own cycle length was 2.6 days from one cycle to the next\, and researc
 hers working from calendar data alone concluded that predicting ovulation 
 from it was not possible.\n\nThis is not contraception and it cannot be ma
 de into contraception. Followed imperfectly\, fertility awareness is about
  76% effective — 24 women in 100 get pregnant in a year — and the NHS 
 does not officially recommend any app or device for it.\n\nGeneral informa
 tion\, not medical advice. When the period actually arrives\, that real da
 te is worth more than any of these.
TRANSP:TRANSPARENT
END:VEVENT
BEGIN:VEVENT
UID:cd39d43339128aba-p5@athenacycle.app
DTSTAMP:20260913T004228Z
DTSTART;VALUE=DATE:20270102
DTEND;VALUE=DATE:20270202
SUMMARY:Period likely to start in this 31-day window (estimate)
DESCRIPTION:The middle of this window is 17 January 2027. It runs 2 January
  2027 to 1 February 2027 — 31 days wide.\n\nWorked out by adding your cy
 cle length to 30 August 2026 5 times over\, and widening it by the shortes
 t and longest cycle you gave: 25 to 31 days.\n\nCycle 5 of 6. Each window 
 is wider than the one before it\, because every cycle in between can move 
 and the movement adds up.\n\nThis block is a window\, not a date. The midd
 le of it is the arithmetic\; the edges are how far the arithmetic can be o
 ut.\n\nCycles move. Across 612\,613 cycles the mean movement in one person
 's own cycle length was 2.6 days from one cycle to the next\, and research
 ers working from calendar data alone concluded that predicting ovulation f
 rom it was not possible.\n\nThis is not contraception and it cannot be mad
 e into contraception. Followed imperfectly\, fertility awareness is about 
 76% effective — 24 women in 100 get pregnant in a year — and the NHS d
 oes not officially recommend any app or device for it.\n\nGeneral informat
 ion\, not medical advice. When the period actually arrives\, that real dat
 e is worth more than any of these.
TRANSP:TRANSPARENT
END:VEVENT
BEGIN:VEVENT
UID:cd39d43339128aba-p6@athenacycle.app
DTSTAMP:20260913T004228Z
DTSTART;VALUE=DATE:20270127
DTEND;VALUE=DATE:20270305
SUMMARY:Period likely to start in this 37-day window (estimate)
DESCRIPTION:The middle of this window is 14 February 2027. It runs 27 Janua
 ry 2027 to 4 March 2027 — 37 days wide.\n\nWorked out by adding your cyc
 le length to 30 August 2026 6 times over\, and widening it by the shortest
  and longest cycle you gave: 25 to 31 days.\n\nCycle 6 of 6. Each window i
 s wider than the one before it\, because every cycle in between can move a
 nd the movement adds up.\n\nThis block is a window\, not a date. The middl
 e of it is the arithmetic\; the edges are how far the arithmetic can be ou
 t.\n\nCycles move. Across 612\,613 cycles the mean movement in one person'
 s own cycle length was 2.6 days from one cycle to the next\, and researche
 rs working from calendar data alone concluded that predicting ovulation fr
 om it was not possible.\n\nThis is not contraception and it cannot be made
  into contraception. Followed imperfectly\, fertility awareness is about 7
 6% effective — 24 women in 100 get pregnant in a year — and the NHS do
 es not officially recommend any app or device for it.\n\nGeneral informati
 on\, not medical advice. When the period actually arrives\, that real date
  is worth more than any of these.
TRANSP:TRANSPARENT
END:VEVENT
END:VCALENDAR