Ruling · Buddha Pūrṇimā (Vaiśākhī Pūrṇimā) · 2026

Thursday 30 April

Boundaryin Chicago, under the Rashtriya Panchang method. A threshold is only 0 min 49 s away. Say “contested”.

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 Thursday 30 April

Taken. The only midday Pūrṇimā reaches.

madhyāhna begins 12:24  13:12 madhyāhna ends
11:3612:0012:2412:4813:1213:3614:00

48 of 48 minutes covered

Midday of Friday 1 May

Pūrṇimā is absent from madhyāhna. Not taken.

madhyāhna begins 12:24  13:12 madhyāhna ends
Pūrṇimā ends 12:23:10
11:3612:0012:2412:4813:1213:3614:00

0 of 48 minutes covered

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

How it was decided

  1. 01

    Aṅga

    Pūrṇimā runs from 10:43 on Thu 30 Apr to 12:23 on Fri 1 May.

    2026-04-30T15:43:06Z → 2026-05-01T17:23:11Z

  2. 02

    Kāla

    Madhyāhna is 1 ghaṭikā either side of midday: 12:24–13:12 on the 30th, 12:24–13:12 on the 1st.

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

  3. 03

    Rule

    Pūrṇimā must be present during madhyāhna. It covers 48 of 48 minutes on the 30th and 0 of 48 on the 1st.

    Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 102

  4. 04

    Tie-break

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

    priority: unstated → only-day · margin 49 s < 300 s

  5. 05

    Ruling

    Buddha Pūrṇimā, Chicago, 2026: Thursday 30 April.

    confidence: boundary (margin)

Say it like this

In Chicago, Buddha Pūrṇimā (Vesak) 2026 falls on Thursday 30 April. Pūrṇimā runs from 10:43 on Thu 30 Apr to 12:23 on Fri 1 May and covers all of madhyāhna that midday. It is 0 min 49 s from a threshold: treat the date as contested.

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

Who says what

AuthorityKindDate
Ahargaṇa, pac-rpThis rulingThu 30 Apr
Ahargaṇa, classicalDisc centre, no refractionThu 30 Apr
compat-drikpanchangComparison profileThu 30 Apr
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/buddha-purnima · ruleset 2026.3-draft

Month
Vaiśākha, amānta
Pakṣa · aṅga
Śukla · Pūrṇimā
Kāla
Madhyāhna
Priority
Unstated
Tie-break
Longer coverage, as a boundary
Reference
CRC 1955, p. 102

“S 15 Sampat gauri vrata (paraviddha), Phuladola (Bengal & Orissa) (paraviddha), Gandhesvari puja (Bengal) (purvaviddha), Buddha purnima, Vaisakhi purnima.” Calendar Reform Committee 1955, General Rules for Religious Festivals, p. 102.

The same rule, elsewhere

Twelve places, west to east. Local clock times.

PlacePūrṇimāMadhyāhna 30thCoveredMadhyāhna 1stCoveredRuled
Los Angeles08:43 → 10:2312:2648 min12:260 min30 Apr
Chicago10:43 → 12:2312:2448 min12:240 min30 Apr
Jersey City11:43 → 13:2312:3048 min12:3048 min30 Apr
Port of Spain11:43 → 13:2311:3944 min11:3948 min1 May
London16:43 → 18:2312:340 min12:3448 min1 May
Durban17:43 → 19:2311:290 min11:2948 min1 May
Dubai19:43 → 21:2311:520 min11:5248 min1 May
Delhi21:13 → 22:5311:550 min11:5448 min1 May
Kolkata21:13 → 22:5311:100 min11:1048 min1 May
Singapore23:43 → 01:2312:380 min12:3848 min1 May
Sydney01:43 → 03:2311:280 min11:2848 min1 May
Suva03:43 → 05:2311:390 min11:3948 min1 May
Profile · tradition
pac-rp@2026.1 · smarta
Rule
buddha-purnima@2026.3-draft
Engine · kernel
0.1.0 · de440 7eef…ea74
Boundary margin
300 s