Ruling · Rādhāṣṭamī · 2026

Friday 18 September

Determinatein Chicago, under the Rashtriya Panchang method. Clear of every threshold by 443 minutes.

Decide it for

ChicagoDelhiKolkataSingaporeSydneyJersey City

41°51′ N 87°39′ W · America/Chicago · GeoNames 4887398

The two middays

One ghaṭī is 24 minutes. Madhyāhna is 1 ghaṭikā either side of midday.

Midday of Friday 18 September

Taken. The only midday Aṣṭamī reaches.

madhyāhna begins 12:20  13:08 madhyāhna ends
11:3211:5612:2012:4413:0813:3213:56

48 of 48 minutes covered

Midday of Saturday 19 September

Aṣṭamī is absent from madhyāhna. Not taken.

madhyāhna begins 12:20  13:08 madhyāhna ends
11:3211:5612:2012:4413:0813:3213:56

0 of 48 minutes covered

Aṣṭamī presentMadhyāhna, the window the rule readsThe instant the tithi begins or ends

How it was decided

  1. 01

    Aṅga

    Aṣṭamī runs from 02:32 on Fri 18 Sep to 04:57 on Sat 19 Sep.

    2026-09-18T07:31:35Z → 2026-09-19T09:57:27Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 12:20–13:08 on the 18th, 12:20–13:08 on the 19th.

    madhyahna: midday-pm-1-ghatika · sunrise and sunset: upper limb, 31′ + 16′

  3. 03

    Rule

    Aṣṭamī must be present during madhyāhna. It covers 48 of 48 minutes on the 18th and 0 of 48 on the 19th.

    Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 103

  4. 04

    Tie-break

    Only one midday qualifies. No tie-break is needed.

    priority: unstated → only-day · margin 26550 s

  5. 05

    Ruling

    Rādhāṣṭamī, Chicago, 2026: Friday 18 September.

    confidence: determinate

Say it like this

In Chicago, Rādhāṣṭamī 2026 falls on Friday 18 September. Aṣṭamī runs from 02:32 on Fri 18 Sep to 04:57 on Sat 19 Sep and covers all of madhyāhna that midday.

ahargana.org/chicago/festivals/2026/radhashtami · pac-rp@2026.1

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingFri 18 Sep
Ahargaṇa, classicalDisc centre, no refractionFri 18 Sep
compat-drikpanchangComparison profileFri 18 Sep
No institution has a recorded ruling for Chicago.

Institutional rulings are recorded with a source address, and are never edited to agree.

The rule, as data

/rules/radhashtami · ruleset 2026.3-draft

Month
Bhādrapada, amānta
Pakṣa · aṅga
Śukla · Aṣṭamī
Kāla
Madhyāhna
Priority
Unstated
Tie-break
Longer coverage, as a boundary
Reference
CRC 1955, p. 103

“S 8 Durvastami (purvaviddha — S 8 of saura Bhadra except Bengal), Mahalaksmi vratarambha, Radhastami (madhyahna vyapini)” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 103.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlaceAṣṭamīMadhyāhna 18thCoveredMadhyāhna 19thCoveredRuled
Los Angeles00:32 → 02:5712:2348 min12:220 min18 Sep
Chicago02:32 → 04:5712:2048 min12:200 min18 Sep
Jersey City03:32 → 05:5712:2648 min12:260 min18 Sep
Port of Spain03:32 → 05:5711:3648 min11:360 min18 Sep
London08:32 → 10:5712:3048 min12:300 min18 Sep
Durban09:32 → 11:5711:2648 min11:2632 min18 Sep
Dubai11:32 → 13:5711:4948 min11:4848 min18 Sep
Delhi13:02 → 15:2711:510 min11:5148 min19 Sep
Kolkata13:02 → 15:2711:070 min11:0648 min19 Sep
Singapore15:32 → 17:5712:350 min12:3448 min19 Sep
Sydney17:32 → 19:5711:260 min11:2548 min19 Sep
Suva19:32 → 21:5711:370 min11:3648 min19 Sep
Profile · tradition
pac-rp@2026.1 · smarta
Rule
radhashtami@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s