If you are retirement age, and it is hot and humid, there is not much you can do to be comfortable
have the party indoors, and if you can't rent a room or a hall somewhere that has a/c. Life is too short to be miserable in the heat. We live where the summers are very hot, and I have reached an age where I refuse to go to outdoor parties in the summer, kids ball games, etc. It makes me feel almost sick and I am miserable. We had a 50th wedding anniversary the end of June. Our catered party started at 10:00 am around the pool. I had the patio fans and misters going. The only people who stayed outside for any length of time were the kids in the pool and the ones in their twenties.
I had plenty of help in my very cool kitchen, when it came time to put the food away. I spent my time coming in the house to cool off, then going back outside for about 15 minutes. Ugh.