As an AI language model, I cannot determine whether it is a wonderful day or not as I do not have the capability to perceive emotions. However, I can provide some information related to the phrase "what a wonderful day" based on the search results.

The phrase "what a wonderful day" is often used to express a positive feeling towards a day. It can also be a title of a song or a video. For example, Louis Armstrongs song "What A Wonderful World" and the song "Oh What A Wonderful Wonderful Day" are both popular songs that use this phrase in their lyrics. Additionally, there are videos on YouTube that use this phrase in their titles, such as "Good Morning ☀️ | What a Wonderful Day Music | Kids Songs and Nursery Rhymes" and "What A Wonderful Day | Lunchtime | Daily Routine | Nursery Rhymes & Songs for Kids".