Days of the week, months, and dates
Two surprises before we start. First: days and months are written in lowercase — segunda-feira, janeiro — unless they open a sentence. Second: the weekdays are numbered, not named. Monday is segunda-feira ('second day'), Tuesday terça-feira, and so on to Friday. Only the weekend gets real names: sábado and domingo.
The seven days
segunda-feira = Monday. terça-feira = Tuesday. quarta-feira = Wednesday. quinta-feira = Thursday. sexta-feira = Friday. sábado = Saturday. domingo = Sunday. In Brazil the -feira half falls off almost every time you speak, and very often when you write: people just say segunda, terça, quarta, quinta, sexta. You'll still meet the full form on schedules and official notices. The five weekday names are feminine (the hidden noun is a feira), so it's a segunda, na sexta; sábado and domingo are masculine: o sábado, no domingo. The two of them together are o fim de semana.
On Monday vs on Mondays
For one particular day, use na (or no for the weekend): na segunda = on Monday, na sexta = on Friday, no sábado = on Saturday. Eu trabalho na segunda. For something that happens every week, Brazil's favourite phrasing is todo / toda: toda segunda = on Mondays, every Monday; todo sábado = on Saturdays. You'll also see the plural forms todas as segundas and, in more careful writing, às segundas. Toda quinta eu tenho aula de português. (In Portugal the habitual is à segunda, singular with à — that one doesn't travel to Brazil.)
The twelve months
janeiro, fevereiro, março, abril, maio, junho, julho, agosto, setembro, outubro, novembro, dezembro. All lowercase, all masculine. Watch março with its ç (an s-sound) and agosto with no accent. To say 'in May', use em with no article: em maio, em janeiro. If you want to be more formal about it: no mês de maio. And remember the seasons are upside down: em julho is winter in Brazil, em janeiro is high summer and school holidays.
Dates: dia 5 de maio
Dates run day, then month, then year, glued together with de: dia 5 de maio = May 5th, dia 12 de março de 2026 = March 12, 2026. The Brazilian habit is to lead with the word dia: Hoje é dia 5 de maio. A festa é no dia 12. (Portugal drops dia and puts an article in front instead — o 5 de maio. In Brazil that sounds like a printed headline, not like speech.) The first of the month is the one day that takes an ordinal: primeiro de maio, written 1º de maio — never um de maio. Written numerically, the day still comes first: 05/05/2026.
Asking what day / what date
Que dia é hoje? = What day is it today? It can be answered either way, and context decides: Hoje é quinta-feira or Hoje é dia 12 de março. To ask specifically for the weekday: Que dia da semana é hoje? To ask specifically for the date: Qual é a data de hoje? For birthdays: Quando é seu aniversário? — É no dia 12 de março. And when you're making plans, the two most useful words are hoje and amanhã: Amanhã é sexta!
Where Portugal does it differently
Same seven days, same twelve months, three small habits apart. Brazil says no sábado where Portugal says ao sábado; Brazil says toda segunda where Portugal says à segunda; Brazil says dia 5 de maio and primeiro de maio where Portugal says o 5 de maio and um de maio. The lowercase rule is identical on both sides of the Atlantic — older Brazilian style capitalized months, but that's long gone. If you hear a Portuguese speaker say fim-de-semana with hyphens, that's just the pre-2009 spelling; Brazil writes fim de semana open.
