Anochecer vs. atardecer vs. crepúsculo
The words 'anochecer', 'atardecer' and 'crepúsculo' are often associated with the transition between day and evening in Spanish. Although they are related to the concept of dusk or nightfall, each word has its own nuance and context of use.
Anochecer
'Anochecer' refers to the time of day when night is about to fall or has just fallen. It is associated with darkness enveloping the sky.
Empieza a anochecer temprano en invierno.
(It starts to get dark early in winter.)
Cuando anocheció, encendimos una fogata.
(When night fell, we lit a bonfire.)
Atardecer
'Atardecer' refers specifically to the late afternoon or early evening that often precedes 'anochecer', when the sun is setting but it's not completely dark.
El atardecer es mi momento favorito para caminar en la playa.
(Sunset is my favorite time for a walk on the beach.)
Los colores del cielo en el atardecer son impresionantes.
(The colors of the sky at dusk are impressive.)
Crepúsculo
'Crepúsculo' is a more poetic term for twilight, which can occur both during dusk and dawn. It refers to the soft glowing light from the sky when the sun is below the horizon. 'Crepúsculo' emphasizes the quality of the light during this transitional time more than the specific time of day.
Durante el crepúsculo vespertino, todo parece más tranquilo.
(During evening twilight, everything seems calmer.)
Nos quedamos despiertos hasta el crepúsculo para ver las primeras estrellas.
(We stayed awake until twilight to see the first stars.)
Summary
While 'anochecer', 'atardecer' and 'crepúsculo' all refer to the transition from day to night, they capture different moments and qualities of this transition. Anochecer' focuses on the onset of night, 'atardecer' on the late afternoon leading into the evening, and 'crepúsculo' on the ambient light present after sunset or before sunrise.