Learn Spanish (Latin America): El concierto termina a la medianoche.

Most times in Spanish are plural, so you use a las (like a las ocho for "at eight"). However, medianoche (midnight) and mediodía (noon) are singular words. Since medianoche is feminine, we use the singular feminine article la, making it a la medianoche.

English just says "at midnight". Why does Spanish add la?

In Spanish, when you talk about the time something happens, you almost always need the definite article (the word for "the") before the time. For midnight, it translates literally to "at the midnight" (a la medianoche).

How do I remember that medianoche is feminine?

Look at the second half of the word: noche (night). The word noche is feminine (la noche), so the combined word medianoche (literally "half-night") keeps that same feminine gender.

Is termina a regular verb?

Yes! It comes from the regular -ar verb terminar (to end or finish). Since el concierto acts as an "it" (third-person singular), you drop the -ar and add -a, giving you termina.