Udo's name day is observed on April 12th in Estonia and October 3rd in Austria.
Udo is a relatively rare name in the USA, but enjoys more popularity in Germany and Estonia. Its origins lie in Old High German, signifying wealth or prosperity, and it’s related to names like Otto and Uta. Historically, it emerged as a standalone name during the medieval period, often as a shortened form. Udo is overwhelmingly masculine, carrying a sense of quiet strength and understated elegance. Its vintage charm suggests a thoughtful and reliable personality, and it feels both classic and slightly mysterious. The name’s rarity offers a unique identity.
| Country | Day | Month | Names |
 Poland | 20 | February | Euchariusz, Eustachiusz, Eustachy, Leon, Ludmiła, Ludomiła, Ostap, Siestrzewit |
| Poland | 1 | March | Albin, Antoni, Antonina, Budzisław, Budzisz, Eudokia, Eudoksja, Ewdokia, Feliks, Herakles, Herkules, Jewdocha, Joanna, Józef, Nikifor, Piotr |
 Spain | 1 | March | Federico, Rosendo, Eudoxia, Eudoxio |
 Estonia | 7 | March | Rudolf, Ruudi, Ruut, Ralf, Rolf, Raul |
 Norway | 27 | March | Rudi, Rudolf |
 Sweden | 27 | March | Ralf, Rudolf |
 Austria | 29 | March | Berthold, Helmut, Ludolf |
| Austria | 17 | April | Eberhard, Rudolph |
 Croatia | 17 | April | Rudolf, Robert |
 Czechia | 17 | April | Rudolf |
 Hungary | 17 | April | Rudolf |
 Latvia | 17 | April | Rudis, Rudolfs, Viviana |
| Poland | 17 | April | Anicet, Innocenta, Innocenty, Jakub, Józef, Klara, Radociech, Robert, Roberta, Rudolf, Rudolfa, Rudolfina, Stefan |
 Slovakia | 17 | April | Rudolf |
| Poland | 7 | May | Benedykt, Bogumir, Domicela, Flawia, Florian, Gizela, Gustawa, Ludmiła, Ludomiła, Sawa, Wincenta |
| Latvia | 27 | May | Dzidra, Gunita, Henrijs, Ludolfs |
| Poland | 21 | June | Albaniusz, Alicja, Alojza, Alojzy, Demetria, Domamir, Marta, Rudolf, Rudolfa, Rudolfina, Teodor |
| Poland | 27 | July | Alfons, Alfonsyna, Aureli, Julia, Laurenty, Lilla, Marta, Natalia, Natalis, Pantaleon, Rudolf, Rudolfa, Rudolfina, Wszebor |
| Poland | 31 | July | Beatus, Demokryt, Emilian, Ernesta, Ernestyna, Helena, Iga, Ignacja, Ignacy, Justyn, Ludomir, Żegota |
 Italy | 25 | August | Ludovico, Vincenzo |
| Slovakia | 25 | August | Ľudovít |
| Spain | 5 | September | Eudosio |
| Slovakia | 14 | September | Ľudomil |
 France | 17 | October | Baudoin, Solène |
 USA | 17 | October | Brad, Braden, Bradford, Bradley, Brady, Braeden, Brayden, Braydon, Rodolfo, Rudi, Rudolf, Rudolph, Rudolphine, Rudy |
| Poland | 2 | November | Ambroży, Bohdana, Bożydar, Eudoksjusz, Małgorzata, Stojmir, Tobiasz, Wiktoryn |
| Austria | 6 | November | Christine, Leonhard, Rudolf |
| Estonia | 9 | November | Teo, Teodor, Tuudor |
| Poland | 10 | November | Andrzej, Lena, Leon, Ludomir, Nelly, Nimfa, Probus, Stefan |
 Denmark | 9 | December | Rudolph |