This is the 119th most frequent Dutch word.
vandaag
"Vandaag" means "today" in English.
In this sentence, 'vandaag' is used to specify the time of the action, referring to 'today' as a particular day.
Vandaag ga ik naar de markt.
Today, I am going to the market.
Here, 'vandaag' functions as part of a phrase modifying the subject 'weather,' providing a temporal context indicating the current day.
Het weer vandaag is erg mooi.
The weather today is very nice.
In this question, 'vandaag' is used to inquire about someone's schedule or availability for the current day.