DJing Outside

Well this is why we recommend good laptops (MacBooks, EliteBooks,…) for DJing. Consumer laptops cannot handle the abuse, only pro-laptops can.
You can try to some degree to help this by adding a cooling pad to your laptop stand. This is basically a pad with fans that you place your laptop on. And also add some fans to your booth to keep the air in the area moving. However if the whole outside air is too hot and moist it will not help.