I am familiar with the word jour, which is a masculine noun meaning "day". This word also shows up in expressions like bonjour and aujourd'hui, making it easy to remember the meaning of these expressions.
But I just learned about the word journée, which also means "day", and now I am confused: when to use jour and when to use journée? For example, if you wanted to say it's a beautiful day today, which word would you use?
C'est un beau jour aujourd'hui. (awkward)
C'est une belle journée aujourd'hui. (sounds better)