When talking about the time using the present tense, use 'es' with one o'clock and 'son' with all other hours. To indicate the quarter hour use 'cuarto'. For the half hour use 'media'.
It is one o'clock.
It is seven o'clock.
It is quarter after nine.
Sample vocabulary that you can use when asking for time or responding.
... in the morning.
... in the afternoon.
... at night.
When the minute hand is between the 1 and 29 minute mark you state the hour plus the minutes using 'y'.
When the minute hand is between 31 and 59 minute mark you state the approaching hour less the minutes using 'menos'.
The following expressions are commonly used when discussing time.