Hoy

Hoy
 

What is the difference between:

hoy and día de hoy

ayer and día de ayer

Why would you choose to say one over the other?:confused:

They mean the same thing. You may sound a bit more formal, or poetic, using the 'redundant' terms, but they are both commonly used, as far as I've heard.

durante todo el día de hoy/ayer = hoy/ayer, durante todo el día
"la oferta termina el día de mañana" -por hoy- (something said yesterday and published today)
el día de la fecha = hoy
y es (al día de hoy/hasta el día de hoy) que nadie sabe dónde está (today; these days; nowadays)

hoy = today (specially "now")
el día de hoy = today (specially "the whole day" or "part of the day")