Iro's designated name day occurs on April 5 in Finland.
The name Iro possesses diverse origins, often stemming from linguistic roots that suggest concepts of distinction or powerful presence. Historically, it has remained very rare in the USA, lacking the widespread usage seen in more common Western names. The name projects a modern and elegant mood, characterized by its short, memorable sound and decisiveness. Iro is broadly classified as a unisex name globally, with specific cultural contexts determining a lean toward male or female usage. Its brief history in American records is often tied to niche cultural or migratory influence rather than general popularity.
| Country | Day | Month | Names |
 Hungary | 18 | January | Piroska |
 Poland | 24 | January | Chwalibóg, Felicja, Mirogniew, Rafaela, Rafał, Tymoteusz |
 Croatia | 1 | February | Brigita, Gita, Miroslav |
 Italy | 9 | February | Girolamo Emiliani |
| Poland | 26 | February | Aleksander, Bogumił, Cezariusz, Dionizy, Mirosław, Nestor |
 Spain | 4 | March | Francisca, Arcadio, Casimiro, Eugenio |
 Bulgaria | 6 | March | Krasimir, Krasimira, Bella, Miroslav, Miroslava |
 Czechia | 6 | March | Miroslav |
| Spain | 11 | March | Ramiro, Oria |
 USA | 11 | March | Alberta, Albertina, Angus, Connie, Constance, Constantine, Consuela, Consuelo, Elberta, Ramiro |
| Spain | 13 | March | Patricia, Rodrigo, Ramiro |
| Spain | 24 | March | Delmiro, Edelmira, Edelmiro, Timolao |
 Slovakia | 29 | March | Miroslav |
| Czechia | 5 | April | Miroslava |
| Slovakia | 5 | April | Miroslava |
| Bulgaria | 5 | May | Irina, Mira, Irena, Miroslav, Miroslava |
| Bulgaria | 11 | May | Kiril, Kirila, Metodi, Kiro, Kirilka, Metodiy, Metodiya |
| Bulgaria | 24 | May | Kiril, Kirila, Metodi, Kiro, Kirilka, Metodiy, Metodiya |
| Spain | 16 | June | Ciro, Aquilino, Aureliano, Siro, Alina, Regina, Regis |
 Latvia | 19 | June | Nils, Vaironis, Viktors |
| Spain | 29 | June | Ciro, David, Siro, Paola, Pablo, Pedro |
| Slovakia | 3 | July | Miroslav |
| Croatia | 14 | July | Kamilo de Lellis, Miroslav |
| Spain | 14 | July | Camila, Vladimiro, Camilo |
| Poland | 26 | July | Anna, Bartolomea, Grażyna, Mirosława |
| Poland | 4 | August | Alfred, Arystarch, Dominik, Maria, Mironieg, Protazy |
 Greece | 17 | August | Miron, Straton |
| Poland | 17 | August | Anastazja, Angelika, Anita, Bertram, Eliza, Jacek, Jaczewoj, Joanna, Julianna, Liberat, Miron, Żanna, Zawisza |
| Poland | 30 | August | Adaukt, Częstowoj, Gaudencja, Miron, Rebeka, Róża, Szczęsna, Szczęsny, Tekla |
 Finland | 7 | September | Miro, Arho, Arhippa, Milo |
| Italy | 30 | September | Girolamo |
| Croatia | 20 | October | Vendelin, Irena, Miroslava |
| Greece | 1 | November | Kosmas, Damianos, Anargiros, David |
 Estonia | 3 | November | Kaido, Kaidu, Kairo, Kaivo, Kaimo, Kaimar |
| Poland | 19 | November | Elżbieta, Mironiega, Paweł, Seweryn, Seweryna |
| Italy | 9 | December | Siro |
| Bulgaria | 12 | December | Darina, Spiro, Spiridon |
| Greece | 12 | December | Spiros |
| Estonia | 19 | December | Maarius, Mario, Mairo |
| Finland | 19 | December | Iiro, Iisakki, Iikka, Isko |