What if I tell you that even we Spaniards don’t always know how to answer in greetings? Example: it’s 1.58pm and you go into a shop —quickly, because they’re about to close for lunch! You are of the polite kind and say “buenas tardes”, but the shopkeeper replies: “buenos días”. Why? Does he/she have a different way to measure time? No, he/she just didn’t have lunch yet. This dilemma is very common with greetings between younger and older people, because the latter tend to have lunch earlier. The same happens with buenas tardes and buenas noches, because unlike most other European languages, which use good night, bonne nuit, gute Nacht or buona notte right before going to sleep, we use the sunlight to separate them, not the bed.

There is an adjective, vespertino, which roughly relates to that time of the day, but it is not used in greetings. And its corresponding noun, víspera, doesn’t help either: it refers to the whole day preceding another one, especially a holiday. Different from its original Latin form, vespĕra, which was something like Archaic English vesper or eventide. The words sobretarde and tardecita seem to refer to that time before the sunset, but they are not common at all in Spain, although the second one seems to be so in Latin America, just as nochecita in some countries. We do have sobremesa, though: as an exercise, try to translate that into English, French, German or Italian, because that’s another cultural-linguistic gap. You may think of table talk, but not all people talk and not always at the table. The RAE dictionary defines it as “time spent at the table after eating”, but I should add “or at a near sofa” (depending on the relationship of the guests [comensales] with the host, or just depending on what’s on TV). And there is no such greeting as buena sobremesa either, but que aproveche or buen provecho before eating. In case you thought of afternoon, that would be more like mediodía for us, which is not used in greetings either. Afternoon, by the way, is also a tough one.

Catalans, as usual, are more European in this topic, because they have vespre. The Spanish influence brought the alien use of bona tarda —almost no one here knows it’s a calque, buy the way—, and then an anti-Castillian hypercorrection gave birth to bona vesprada (more common in the Valencian variant) to complicate things more. Funny enough, a Catalan-Spanish dictionary translates vespre as “anochecer, atardecer | (a partir de les vuit –from 8 pm-) noche”. As if it was so simple.

And one last thought: why are Spanish greetings used in plural while other languages (even geographically adjacent, like Portuguese, French, Catalan, Galician) use the singular? Maybe because of respect, as in gracias, saludos, recuerdos, felicidades, felices fiestas (but not feliz Año Nuevo, feliz Navidad); maybe because in the past long distances prevented people to meet frequently and therefore used to wish each other well for many days, not just for one… but that’s not clear at all. Some Latin American countries do say “buen día”, and it is common to hear “que tengas un buen día/una buena tarde/una buena noche”, but that only brings more questions, doesn’t it?

So no, stop looking, sorry, there is no such word for evening, soir, sera, Abend in Spanish.

And as for farewell words, we could start another discussion about adiós, because very few people use that word as a greeting nowadays in Spain, contradicting all language books. Probably because it sounds too drastic, as if you were not going to meet that person any other time in your life. Therefore, most people prefer hasta luego, even though they know they will not meet «later», but some other day (or never at all). Hasta pronto would be more appropriate, but it is not common either. I only hear adiós quite often here in Catalonia among elder people, as a literal translation of Catalan adéu, which is the most frequent farewell word even if you’re speaking Spanish.
Similarly, funny situations may arise with ¿qué tal? as a greeting after hola: as far as I know, in most Spanish regions people expect a short answer like «bien, ¿y tú?», «bien también, gracias» or «ahí vamos» and then complain about the government. But in other places, like Madrid, many people say it as an empty greeting, as they don’t expect any answer at all. So don’t get upset if a stranger says «hola, ¿qué tal?» to you in the middle of the street, and when you try, as surprised as you may be, to start a conversation, you find that your «greeter» is already far away.