Based solely on the provided information, the name day for Tia in the USA is established as January 5.
Tia is a concise, feminine name that gained notable traction in the USA during the latter half of the 20th century, particularly peaking in popularity around the 1980s. Historically, it functions as a short form for longer feminine names like Letitia, though it is also recognized independently in Spanish as the word for "aunt." Its origin sometimes connects it to Greek concepts of the divine or the Latin root *Dea*, meaning goddess. Globally, Tia is classified definitively as a female name. The name carries an energetic, playful, and elegantly modern mood, suggesting a bright and approachable personality. This simple yet sophisticated choice remains consistently familiar in American naming culture.
| Country | Day | Month | Names |
 Bulgaria | 12 | January | Tanya, Tatyana, Tatiana |
 France | 12 | January | Tatiana |
 Greece | 12 | January | Mertios, Tatiana |
 Spain | 12 | January | Alfredo, Tatiana, Tania, Hilario |
 Ukraine | 12 | January | Tetiana, Tania |
 Denmark | 19 | January | Pontianus |
| Spain | 19 | January | Mario, Vicente, Sebastián |
 Austria | 20 | January | Fabianus, Sebastian, Ursula, Ute |
| Denmark | 20 | January | Fabian, Sebastian |
 Finland | 20 | January | Sebastian |
 Germany | 20 | January | Fabian, Paula, Sebastian |
 Norway | 20 | January | Bastian, Fabian, Sebastian |
 Poland | 20 | January | Dobiegniew, Fabian, Sebastian |
 Slovakia | 20 | January | Dalibor, Sebastián |
 Sweden | 20 | January | Fabian, Sebastian |
 USA | 20 | January | Fabia, Fabian, Fabiola, Sebastian, Sebastiana |
 Italy | 21 | January | Sebastiano |
| USA | 22 | January | Enoch, Piper, Vicenta, Vicente, Vince, Vincent, Vincentia, Vincenzo, Vinnie |
| Poland | 25 | January | Miłosz, Miłowan, Miłowit, Paweł, Tacjanna, Tatiana |
| Poland | 30 | January | Adelajda, Feliks, Gerard, Gerarda, Gerhard, Hiacynta, Maciej, Marcin, Martyna, Sebastian |
| Slovakia | 1 | February | Tatiana |
| Greece | 3 | February | Asimina, Malamati, Stamatis, Stamatia |
| Poland | 8 | February | Gniewomir, Gniewosz, Honorat, Jan, Ksenofont, Lucjusz, Paweł, Piotr, Salomon, Sebastian, Żaklina |
| Spain | 13 | February | Cristian, Benigno |
| Poland | 18 | February | Albert, Alberta, Albertyna, Fryda, Konstancja, Krystiana, Maksym, Sawa, Sylwan, Sylwana, Symeon, Więcesława, Zula, Zuzanna |
| Denmark | 24 | February | Mattias |
 Estonia | 24 | February | Mattias, Madis, Madi, Matis, Mati, Matti, Mats, Mait, Maido, Maidu, Mäido |
| Finland | 24 | February | Matias, Matti |
| Norway | 24 | February | Mathias, Mats, Mattias, Mattis |
| Sweden | 24 | February | Mats, Mattias |
| USA | 24 | February | Maddison, Madison, Madisyn, Madyson, Mateo, Mathew, Mathias, Matt, Mattea, Matthew, Matthias, Mattias, Mattie, Matty, Modesto |
| Greece | 26 | February | Porfyros, Sebastian, Fotini, Anatoli, Fay |
| Ukraine | 26 | February | Sebastian |
 Hungary | 13 | March | Krisztián, Ajtony |
| Austria | 21 | March | Axel, Christian, Emilia |
| Austria | 5 | April | Crescentia, Vinzenz |
| Spain | 29 | April | Teodora, Karen, Katia, Wilfredo, Catalina |
| Austria | 14 | May | Bonifatius, Christian |
| Denmark | 14 | May | Kristian |
| Italy | 14 | May | Mattia |
| Norway | 14 | May | Karsten, Kristen, Kristian |
| Spain | 14 | May | Matías, Corona, Cora, Henedina, Alba, Gemma |
| Denmark | 19 | May | Potentiana |
| Ukraine | 24 | May | Christian |
| Hungary | 6 | June | Norbert, Cintia |
| Greece | 7 | June | Sevastianis, Sevasti, Sebastian |
| Ukraine | 15 | June | Krystsentia |
| France | 30 | June | Adolphe, Martial |
 Latvia | 24 | July | Krista, Kristiana, Kristine, Krists |
| USA | 24 | July | Amalia, Amelia, Boris, Chris, Christa, Christen, Christian, Christiana, Christie, Christin, Christina, Christine, Christy, Chrysta, Cristina, Cristian, Declan, Kiersten, Kirsten, Kirstie, Kirstin, Krista, Kristen, Kristian, Kristi, Kristin, Kristina, Kristine, Kristy, Kristyn, Maya |
| Spain | 25 | July | Jaime, Santiago |
| USA | 25 | July | Coby, Colby, Diego, Israel, Jack, Jackie, Jackson, Jaclyn, Jacob, Jacoby, Jacqueline, Jacquelyn, Jacques, Jaime, Jake, Jakob, James, Jameson, Jamie, Jaquan, Jaqueline, Jaxon, Jaxson, Jim, Jimena, Jimmie, Jimmy, Kobe, Koby, Kolby, Santiago |
| Greece | 2 | August | Justianos |
 Czechia | 5 | August | Kristian |
| Austria | 13 | August | Cassian, Hippolyt, Marko, Pontianus |
| France | 18 | August | Hélène, Laétitia |
| Norway | 13 | September | Stian, Stig |
| USA | 14 | September | Keisha, Lakeisha, Latasha, LaTease, Latisha, Leticia, Letitia, Letty, Tish, Tisha |
| Poland | 16 | September | Antym, Cyprian, Edda, Edyta, Eufemia, Eugenia, Franciszek, Jakobina, Kamila, Kornel, Lucja, Łucja, Sebastiana, Sędzisław, Wiktor, Wiktoriusz |
| Denmark | 19 | September | Constantia |
| Slovakia | 19 | October | Kristián |
| Greece | 24 | October | Sevastianis, Sebastian |
| USA | 5 | November | Perdita, Tiara, Tiera, Tierra, Swain, Swana |
| France | 12 | November | Christian |
| Finland | 13 | November | Ano, Kristian |
| Sweden | 13 | November | Krister, Kristian |
| Poland | 4 | December | Barbara, Berno, Biernat, Chrystian, Hieronim, Krystian, Piotr |
| Austria | 15 | December | Carlo, Christiane, Nina |
| Poland | 15 | December | Celina, Fortunata, Iga, Ignacja, Ignacy, Krystiana, Nina, Walerian, Waleriana, Wolimir, Żegota |
| Greece | 18 | December | Floros, Sebastian |
| Bulgaria | 25 | December | Hristina, Hristo, Kristina, Kristian, Kristiana, Emil, Itso, Icho, Mladen, Radoslav, Radoslava, Radomir, Radostin, Radostina, Hristofor |
| Poland | 31 | December | Korneliusz, Mariusz, Melania, Sebastian, Sylwester, Tworzysław |