SAPIR 861 · A MEASUREMENT · 1800–2100

No Hebrew date falls on all seven weekdays

A Hebrew date does not wander freely through the week. We counted every day from 1800 to 2100 and found that no Hebrew day of the month can fall on all seven weekdays. This follows from the rules of the fixed calendar, but we have not seen it published as a measurement.

The headline figure

267

Hebrew dates out of 385 are limited to exactly four weekdays

dates can fall on all seven weekdays — Not one.

How many weekdays a date can reach

Weekdays	Dates	Share
3	1	0.3%
4	267	69.4%
5	88	22.9%
6	29	7.5%
7	0	0%

The only date with three possible weekdays is 30 Cheshvan, and it exists in just 135 of the 301 years. A check against something known: 15 Nisan falls only on Sunday, Tuesday, Thursday and Saturday — the classical lo BaDU Pesach, obtained here from the data rather than quoted.

How many portions a date can meet

Distinct portions	Dates	Share
1	30	7.8%
2	220	57.1%
3	82	21.3%
4	38	9.9%
5	15	3.9%

The maximum is five, and only for dates around Passover, where festival readings intervene.

Thirty locked dates

For these dates the portion is the same in all 301 years. All of them sit near Tishrei: the further from it, the wider the spread.

Date	Portion	Years out of 301
3 Av	Devarim	301
4 Av	Devarim	301
10 Av	Vaetchanan	301
11 Av	Vaetchanan	301
17 Av	Eikev	301
18 Av	Eikev	301
24 Av	Re'eh	301
25 Av	Re'eh	301
1 Elul	Shoftim	301
2 Elul	Shoftim	301
8 Elul	Ki Teitzei	301
9 Elul	Ki Teitzei	301
15 Elul	Ki Tavo	301
16 Elul	Ki Tavo	301
23 Tishrei	Bereshit	301
24 Tishrei	Bereshit	301
30 Tishrei	Noach	301
1 Cheshvan	Noach	301
7 Cheshvan	Lech-Lecha	301
8 Cheshvan	Lech-Lecha	301
14 Cheshvan	Vayera	301
15 Cheshvan	Vayera	301
21 Cheshvan	Chayei Sara	301
22 Cheshvan	Chayei Sara	301
28 Cheshvan	Toldot	301
29 Cheshvan	Toldot	301
6 Kislev	Vayetzei	301
13 Kislev	Vayishlach	301
20 Kislev	Vayeshev	301
27 Kislev	Miketz	301

How it was counted

Range: 1800–2100 in the Gregorian calendar, 301 years, 109,938 observations. There is no sampling: every day was counted.
Calendar: The fixed Hebrew calendar as implemented in hebcal. No assumptions beyond the rules of the calendar itself.
The week of a date: The week is taken to end on the following Shabbat. The portion is the one read on that Shabbat; festival readings take precedence over the weekly portion.
Reading cycle: Diaspora. In the Land of Israel the schedule differs by one portion in some years — that is a separate calculation.

The dataset

A table of all 385 dates: how many years the date exists, which weekdays are possible, which are impossible, and every portion with its count. Free use with attribution.

Download the table (CSV, 385 rows)

Cite as:

SAPIR 861 (2026). Weekday and portion distribution of Hebrew calendar dates, 1800–2100. Dataset and method. https://sapir861.com/hd

Sources

Calendar: hebcal. Portion boundaries: hebcal leyning. Both are public; anyone can repeat the count and get the same numbers.

Every date on its own page

No Hebrew date falls on all seven weekdays

The headline figure

How many weekdays a date can reach

How many portions a date can meet

Thirty locked dates

How it was counted

The dataset

Sources

Every date on its own page

Nisan

Iyyar

Sivan

Tamuz

Av

Elul

Tishrei

Cheshvan

Kislev

Tevet

Shvat

Adar / Adar I

Adar II

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