Coastal areas will be humid but I guess you are used to that in Dubai and it will be immeasurably more comfortable
Further inland and up in the mountains it will be fresher and cooler.
One of the (many) things I like about KSA is the dry desert heat. 55C is quite bearable if you're careful.
I imagine you've done your research so you know the areas to stay away from, both in BEY and the wider country. Are you escaping Ramadan ? It's not really an issue in BEY.
Take care. They certainly know how to party