Is the word maio the same in Brazilian and European Portuguese?

Yes

The word "maio" (referring to the month of May) is identical in spelling, meaning, and grammar in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, vowels are generally more open and clearly articulated, giving the word a more "musical" quality. In Continental Portuguese, vowels that are not stressed tend to be more closed or even reduced (devoiced), which can make the diphthong sound slightly more compressed.

Brazilian Portuguese Examples

1. Meu aniversário é em maio. (My birthday is in May.)
2. Eu vou viajar em maio. (I am going to travel in May.)
3. O calor de maio é muito bom. (The May heat is very good.)
4. As flores de maio são lindas. (The May flowers are beautiful.)
5. O feriado de maio está chegando. (The May holiday is coming.)

Continental Portuguese Examples

1. O meu aniversário é em maio. (My birthday is in May.)
2. Eu vou viajar em maio. (I am going to travel in May.)
3. O calor de maio é muito bom. (The May heat is very good.)
4. As flores de maio são lindas. (The May flowers are beautiful.)
5. O feriado de maio está a chegar. (The May holiday is coming.)