This is the 9588th most frequent Catalan word.
is
The Catalan word "is" does not exist; it may be a misunderstanding or typo.
Here, 'és' is used as the third person singular of the verb 'ser', expressing an attribute or identification.
Aquesta és la meva casa.
This is my house.
In this sentence, 'és' links the subject 'avui' with its characteristic 'un dia solejat', describing the day.
Avui és un dia solejat.
Today is a sunny day.
In this case, 'és' serves to state a relationship or identity between Joan and the speaker.