In Jainism, “when the date changes” is understood a bit differently from the normal (12‑midnight) civil date.

Very simple points:

1. One Jain “day” = from sunrise to next sunrise

- For most vrats (upvās, beyāsan, ayambil, etc.) and paap–puniya counting, the day is taken from today’s sunrise up to tomorrow’s sunrise. - So if you did upvās today, it means: no food from today’s sunrise till next day’s sunrise.

1. Tithi (lunar date) is decided by sunrise, not by midnight

- In Jain practice, the important rule is usually: Which tithi is running at local sunrise? That is counted as that day’s tithi. - Because of this, your Jain tithi “date change” effectively happens at sunrise, not at 12:00 am.

1. Why this is important

- For deciding: - which day to do a particular vrat or festival (Paryushan tithi, Ashtami, Chaturdashi, etc.), - how to count fasts (e.g. 16 upvās, olī, etc.), - when a special tithi ends and the next one starts for dharmic purposes. - Panchāng (Jain calendar) may show tithi changing at any clock time, but for observance we mainly see which tithi is at sunrise.

1. Midnight vs. sunrise – both exist, but for different use

- Government / normal calendar: day changes at 12 midnight – for office, school, tickets, etc. - Jain dharma view: for vrat, paap‑puniya, tithi, tapas, the important “date change” is sunrise to sunrise.

So, in Jainism, when you are asking “when date changes (this is important)”, for religious purposes you should think: “New Jain day and tithi for dharmic work start from sunrise, not from midnight.”