Son las doce.	It's twelve o'clock.
A las doce.	At twelve o'clock.
Es medianoche.	It's midnight.
Al mediodía.	At midday.
Son las veinticuatro horas.	It's 24 hundred hours.

Es la una del medio día.	It's one o'clock in the afternoon.
A la una de la mañana.	At one o'clock in the morning.
Son las trece horas.	It's thirteen hundred hours.

Es la una y media de la tarde.	It's one thirty in the afternoon.
A la una y media.	At one thirty.
Son las trece y treinta horas.	It's thirteen thirty hundred hours.

Son las once y quince.	It's eleven fifteen.
A las once y quince.	At eleven fifteen.
Son las veintitrés y quince horas.	It's twenty three fifteen hundred hours.

Son las nueve y veinticinco.	It's eleven fifteen.
A las nueve y veinticinco.	At eleven fifteen.
Son las veintiuno y veinticinco horas.	It's twenty one twenty five hundred hours.

Son las tres menos veinte.	It's twenty to three / two forty.
Es veinte para las dos.	It's twenty to three / two forty.
A las tres menos veinte.	At twenty to three / two forty.
Son las catorce y veinte horas.	It's fourteen forty hundred hours.

Son las seis menos cinco.	It's five to six / five fifty five.
Son las cinco y cincuenta y cinco.	It's five to six / five fifty five.
A las seis menos cinco.	At five to six / five fifty five.
Son las cinco y cincuenta y cinco horas.	It's seventeen fifty five hundred hours.

¿Qué fecha es? - What date is it?

lunes	Monday	enero	January	agosto	August
martes	Tuesday	febrero	February	septiembre	September
miércoles	Wednesday	marzo	March	octubre	October
jueves	Thursday	abril	April	noviembre	November
viernes	Friday	mayo	May	diciembre	December
sábado	Saturday	junio	June	Note: No capital letters are used in          Spanish
domingo	Sunday	julio	July

Es martes veintidós de julio.	It's Tuesday the twenty second of July.
Es sábado 25 de Diciembre.	It's Saturday 25th December.
In Spanish cardinal number (1st / 2nd etc), are not commonly used with dates.
En Mayo. El diez (10) de Mayo.	In May. The tenth (10th) of May.

Useful phrases

los lunes, martes, etc)	Mondays, Tuesdays etc	por la mañana / tarde	in the morning / evening
hoy, mañana, esta tarde, esta noche	today, tomorrow, this afternoon tonight	ayer / anteayer	yesterday / the day before yesterday
el jueves que viene	this Thursday	anoche / anteanoche	last night / the night before last
la semana / el mes / año pasada	last week / month / year	hace (dos días semanas / meses /años	two days / weeks / months / years ago
dentro de seis meses	within six months	pasado mañana	the day after tomorrow

Note: In Spanish 'son' and 'las' are used when telling the time with all hours except from one o'clock until one fifty           nine. In these cases 'una' and 'la' are used.