When having your hair and makeup done for an event taking place outdoors in humid weather, it's important to consider that hairstyling and makeup application, as well as the amount of product used will be different than if you would have an indoor event with AC or even an outdoor event with cooler temperature.
The intention is for it to last the whole event no matter what, specially to look on point for pictures, but there are many factors to consider, one of them the humidity level.
Hair and makeup technique and product application will depend mostly on:
Your hair and face texture
The type of hairstyle & makeup look
So depending on the case, like for example in humid weather, you will most likely have to wear much more hair product and volume, and slightly more layers of makeup at first. All of this will eventually soak into your skin and hair as the day goes on.
Think of it as a protective layer between you and the sauna-like weather, and that eventually will blend with your skin and hair.