Oh, that is super hot! No wonder you are uncomfortable. Too many long pants and too much denim. Even white denim, which looks lovely and cool, can still feel hot in such heat. A casual day dress would be so helpful in this situation. Hmmm. I don't suppose you have a friend of a similar size (and taste)? Perhaps someone could lend you something. I have been on both ends of that from time to time while travelling.
This is not a fail on your part. Weather can be so unpredictable and even if temperatures are listed, it can be difficult for us to imagine how 37 will feel if we are living in temps of 20 or so when we pack. I have a similar problem if I am going anywhere warmer during my winter.
This is why I separate my summer and winter clothes and don't keep them hanging all together. It's just impossible for me to make sense of the voile blouse and the heavy wool sweater at the same time!