The difference in meaning is very little, indeed; Both 'mattino' and 'mattina' refer to A) the time of day B) the human activities during that time If the emphasis is on (A), like in the weather forecasting (previsioni [del] meteo), use 'mattino' If the emphasis is on (B), then use 'mattina' But the rule is absolutely not strict. Sometimes you need this meaning as a complement of something else, like Sunday morning; here you must use: Domenica mattina; or Domenica al mattino (correct but rarely used) Sorry to say, that the related particles do vary: (a '+' sign points to the form more often used) + -- cosa fai domani mattina ? -- cosa fai domani al mattino ? + -- mi sveglio di mattina alle 6 per rispondere a Italki -- mi sveglio al mattino alle ... ++ - ci vediamo di nuovo domani mattina - ci vediamo di nuovo domani al mattino ++ -- prevista nebbia in Val Padana al mattino -- prevista nebbia in Val Padana di mattina With 'ogni', tutti, use mattina: -- ogni mattina veniva nella mia libreria la donna che poi ho sposato -- tutte le mattine il GRA intorno a Roma e` pieno di traffico (Gra: grande raccordo anulare: circular highway around Rome) All in all 'mattina' means both 'mattino' and 'durante il mattino', although sometimes you should also add 'di' with 'mattina'.