Mia’s name day is observed on July 13 in Norway and on September 29 in the USA.
Mia is a predominantly female name that has seen explosive popularity in the USA, rising quickly into the top ranks of feminine names over the last two decades. Originating often as a diminutive of Maria, its meaning is frequently interpreted as "beloved" or the possessive pronoun "mine" in certain languages. Historically, the short form gained traction in European countries before becoming a global phenomenon. The name projects a mood that is light, elegant, and playful yet possesses a classic sophistication. It maintains a universally feminine gender identity across continents. This simple structure contributes to its approachable and universally appealing tone.
| Country | Day | Month | Names |
 Poland | 19 | January | Andrzej, Bernard, Erwin, Erwina, Eufemia, Henryk, Kanut, Mariusz, Marta, Matylda, Mechtylda, Pia, Racimir, Sara |
 Bulgaria | 20 | January | Eftim, Efimir, Evtim, Evtimiya, Evtimia, Momchil |
 Greece | 29 | January | Varsamia |
 Spain | 16 | February | Elías, Samuel, Isaías, Jeremías |
 USA | 16 | February | Cliff, Clifford, Clifton, Jeremiah, Jeremy, Sonnie, Sonny, Sunny |
| Spain | 21 | February | Irene, Pedro Damián |
 Italy | 22 | February | Pier Damiani |
| Poland | 23 | February | Bądzimir, Damian, Florentyn, Łazarz, Piotr, Roma, Romana, Seweryn |
 Austria | 5 | March | Dietmar, Jeremia, Olivia |
| Poland | 20 | March | Aleksander, Aleksandra, Ambroży, Anatol, Bogusław, Cyriaka, Eufemia, Klaudia, Patrycjusz, Ruprecht, Wasyl, Wincenty |
| Spain | 12 | April | Andrés, Damián, Julio, Zenón |
| Austria | 15 | April | Anastasia, Damian, Una |
| Poland | 1 | May | Aniela, Filip, Jakub, Jeremi, Jeremiasz, Józef, Lubomir |
 Ukraine | 1 | May | Jeremiah, Jeremy, Tamara |
| Spain | 2 | May | Germán, Araceli, Atanasio, Vindemial, Exuperio, Zoé, Mafalda |
| Poland | 14 | May | Bończa, Bonifacy, Dobiesław, Jeremi, Jeremiasz, Wiktor, Wiktoriusz |
 Denmark | 7 | June | Jeremias |
| Bulgaria | 17 | June | Asparuh, Krum, Asen, Chavdar, Rumiana, Rumen, Momchil, Desislava |
 Finland | 26 | June | Jarmo, Jorma, Jarkko, Jarno, Jere, Jeremias |
| Poland | 26 | June | Jan, Jeremi, Jeremiasz, Paweł, Zdziwoj |
| Greece | 1 | July | Kosmas, Damianos, Damian |
| Poland | 14 | July | Bonawentura, Damian, Dobrogost, Franciszek, Izabela, Kosma, Marceli, Marcelin, Marcelina, Stella, Ulrych, Ulryk, Ulryka |
| USA | 14 | August | Anahi, Athena, Tamara, Tamia, Tammie, Tammy, Tara, Taryn, Terra |
| Poland | 3 | September | Antoni, Bartłomiej, Bazylissa, Bronisław, Bronisz, Erazma, Eufemia, Eufrozyna, Izabela, Jan, Joachim, Joachima, Manswet, Mojmir, Szymon, Wincenty, Zenon, Zenona |
| Denmark | 16 | September | Euphemia |
 Germany | 16 | September | Cornelius, Euphemia |
| Poland | 16 | September | Antym, Cyprian, Edda, Edyta, Eufemia, Eugenia, Franciszek, Jakobina, Kamila, Kornel, Lucja, Łucja, Sebastiana, Sędzisław, Wiktor, Wiktoriusz |
| Austria | 26 | September | Cosima, Damian, Kosmas |
| Italy | 26 | September | Cosma, Damiano |
| Spain | 26 | September | Cosme, Damián |
| Poland | 27 | September | Amadeusz, Amedeusz, Damian, Kosma, Przedbor, Urban |
| USA | 27 | September | Cosima, Cosimo, Cosmo, Damian, Damiana, Damien, Damion, Damon |
| Spain | 20 | October | Academia, Irene |
| Greece | 1 | November | Kosmas, Damianos, Anargiros, David |
| Poland | 14 | November | Aga, Agata, Damian, Elżbieta, Emil, Emiliusz, Jozafat, Józef, Judyta, Kosma, Laurenty, Lewin, Ścibor, Ścibora, Serafin, Wszerad |
Norway