I guess I have to keep in mind that masculine words in the genitive case look the same as when they're in the accusative case.
Can I ask someone, what about neuter nouns in the genitive case? If I remember rightly they look the same in nominative as they do in accusative. Is 'lato' a neuter noun?
It is neuter. But Genitive of it is "lata", so it's different than the Accusative.
The singular Genitive of a neuter noun is the same as the Nominative plural, if I am not wrong.
It works, but it's too grammatically different to be the main answer. We can say the same in Polish: "Lipiec to letni miesiąc". Although that doesn't seem that common to me as its English equivalent.