Different appellations for the days of the week and the months

Funny how similar languages can have different words to designate the days of the week and the months. Portuguese and Spanish days of the week are completely different, except for two identical ones. Czech months have Slavic names, but the Slovak ones are Latinate. Croatian months are also Slavic, but not similar to the Czech ones. There are even two that refer to different months in Czech; one, though, is the same, the word for December. Serbian, very close to Croatian, has Latinate names, like Slovak.