N.B.
Let's say he has her for the whole month of June.That includes the first and third weekends.
If he gets her in the middle of the month and one of those designated weekends are not included then I would say yes, that's his weekend.
If he isn't wanting to take her on those weekends but you planned her being gone then you can request he find someone in his family or something to watch her. Otherwise I would say any time it's his weekend or that he wants to see her he should have access to her.
It's sooo much easier to have a decree that states specific dates.
For example.
Guy will have daughter from June 1st through June 30 and from that point through the rest of the summer break from school he will continue his scheduled visitation on the 1st and 3rd weekend.
Or
Guy will have daughter from June 1st through July 31st. Then his regular visitation will commence. He will have her, regardless of holiday or celebration on those 2st and 3rd weekend.