Question

What is the difference between the questions. "¿Qué hora es? and "¿A qué hora es ...?"

¿Qué hora es? is used in the morning and ¿A qué hora es...? is used in the evening.

They are written differently, but they ask the same question.

¿Qué hora es? asks for the time and ¿A qué hora es...? asks at what time.

¿A qué hora es..." used when you are speaking formally.

Answer 1

Short answer
- ¿Qué hora es? = What time is it? (asks for the current time.)
- ¿A qué hora es ...? = At what time is ...? (asks when a planned event starts.)

Corrections to the incorrect statements you wrote
- They are not split by morning/evening — both can be used any time of day.
- They are not a formal vs. informal distinction — both are neutral and equally fine in formal or informal contexts.

Details and examples
- ¿Qué hora es?
- Use when you want the current time.
- Answers: Es la una. / Son las tres. / Son las nueve y cuarto.
- Example: — ¿Qué hora es? — Son las dos y diez.

- ¿A qué hora es ...?
- Use when asking when an event happens or will happen.
- The preposition a + qué = "at what" (so you are asking for a time for an event).
- Common forms: ¿A qué hora es la reunión? ¿A qué hora sale el tren? ¿A qué hora empieza la película?
- Answers: Es a las cinco. / A las siete. / Empieza a las ocho.

Small grammar notes
- For current time: use es la (1:00) or son las (other hours).
- For events: you can say "Es a las..." or simply "A las..." (A las tres, por ejemplo).

If you want, I can give more examples or short practice dialogues.