Breakdown of Завтра будет среда, шестое марта, и у нас будет короткий урок.
Questions & Answers about Завтра будет среда, шестое марта, и у нас будет короткий урок.
Russian does not need a dummy subject like English it in expressions about time, dates, or weather.
So:
- Завтра будет среда = literally Tomorrow will be Wednesday
- natural English = Tomorrow it will be Wednesday
In Russian, будет среда is a normal impersonal-style statement about the calendar.
Because шестое does not agree with среда.
In Russian dates, the day number is usually understood as an omitted neuter noun: число (date / number). So шестое марта is really:
- шестое (число) марта = the sixth of March
That is why шестое is neuter singular. It is not describing среда; it is giving a separate piece of information: the calendar date.