¿Tiene hora?

Is it morning or evening?

In many Spanish-speaking countries, you'll use the 24-hour clock, so you won't need to clarify whether that dentist appointment is at two in the afternoon, or two in the morning.

But in case you do, you'll do it like this:

Son las dos de la mañana
It's two in the morning

Son las dos de la tarde
It's two in the afternoon

Son las ocho de la noche
It's eight in the evening

When does "the night" start?

In most English speaking countries you'd probably start talking about "the night/evening" around 6pm. But in a lot of Spanish-speaking countries, you wouldn't roll out the "de la noche" until around 8pm.

How to say midday - Es el mediodía
                                  It's noon / midday

How to say midnight - Es la medianoche
                                     It's midnight

Son las ocho en punto - It's exactly 8 o'clock

Casi son las ocho - It's nearly 8 o'clock

Saying when something will happen

When you want to talk about what time a class is, or what time you'll meet someone, you'd use "at" in English. ("I'll meet you at seven"). In Spanish you'll use "a las..."

Tengo mi clase de español a las cinco
I have my Spanish class at five

¿Nos encontramos a las siete?
Shall we meet at seven?