Pitman's Commercial Spanish Grammar (2nd ed.)

by C. A. Toledano

The principal =Impersonal Verbs= are—

Llover-llueve (to rain, it rains)
Granizar (to hail)
Helar-hiela (to freeze, it freezes)
Lloviznar (to drizzle)
Nevar-nieva (to snow, it snows)
Relampaguear (to lighten)
Tronar-truena (to thunder, it thunders)
Alborear (to dawn)
Amanecer (to dawn)
Anochecer (to grow dark)

The subject (generally understood) of Impersonal verbs is ello. Sometimes we find the words Dios or el día expressed as subjects, as—

Amanecerá Dios y veremos: Let us wait for the morning and then we shall see.

Amaneció el día: The day dawned.

Amanecer and anochecer may be used as personal verbs, as—

Amanecimos en Madrid y anochecimos en Guadalajara: We were in Madrid at daybreak and at nightfall in Guadalajara.

Tú anocheciste bueno y amaneciste malo: You passed the night well, but you had a bad morning.

Many ordinary verbs are used sometimes impersonally, as—

Bastar (to suffice).
Convenir (to suit).
Parecer (to appear).
Faltar[130] (to be wanting).
Hacer falta (to be wanted).
Suceder[131] (to happen).