Dates & calendar

• Date order: day / month / year (31/12/2024)

• Months are never capitalized: janeiro, fevereiro…

• Only the 1st is ordinal: primeiro de maio

• Days 2–31 are cardinal: dois, três, quinze…

• Weekdays are numbered: segunda-feira (Monday) … sexta-feira (Friday)

• Written dates: DD/MM/AAAA (or DD/MM/AA)

• Prepositions: em + month/year, no dia + date

• Years take de: 15 de março de 2024

Dates run everything in Brazil — booking your visa appointment (dia quinze de março), knowing when Carnaval lands (terça-feira de carnaval), and dodging the day/month mix-up (03/04 is April 3rd, not March 4th!). Get the order wrong and you show up for your medical exam a month late, or read 05/06 as May 6th and miss your June 5th flight. And don't forget the flipped seasons — pack for verão, not winter, on a January beach trip!

The date formula

Brazilian dates follow one pattern:

(dia) + número + de + mês + de + ano

• 25 de dezembro de 2024 (December 25, 2024)

• 7 de setembro de 1822 (September 7, 1822)

• 1º de janeiro (January 1st — only the 1st is ordinal!)

Days of the month

Making plans

• "Nos vemos dia 15." (See you on the 15th.)

• "A reunião é segunda-feira." (The meeting is Monday.)

• "Volto em março." (I'm coming back in March.)

• "Marcamos para o dia 20 de junho." (We're set for June 20.)

Birthdays

• "Meu aniversário é 12 de outubro." (My birthday is October 12.)

• "Faço anos dia 30." (My birthday's on the 30th.)

• "O Ano Novo é no dia primeiro de janeiro." (New Year is on January 1st.)

Booking & appointments

The American-date trap

The most common mistake — reading dates American-style:

• Brazil: 03/04 = April 3rd (day first!)

• USA: 03/04 = March 4th
  In Brazil the day always comes first.

The "primeiro" rule

Only the first of the month is ordinal:

• ✅ "primeiro de janeiro" · ❌ "segundo de janeiro" → ✅ "dois de janeiro"

• ❌ "terceiro de março" → ✅ "três de março"

Dropping "-feira"

Don't reach for February 14! Brazil celebrates Dia dos Namorados (its Valentine's) on 12 de junho, the eve of Dia de Santo Antônio — the santo casamenteiro, or "matchmaker saint". The date was actually dreamed up by a São Paulo ad campaign in 1949 to lift slow June sales, and it caught on so completely that Brazil never adopted the February version.

Sources: CNN Brasil, National Geographic Brasil