I officiate in the Delaware/Pennsylvania/Maryland area. Summers are hot and very humid. Evaporative cooling vests and neck cooling towels do not work well here. Ice vests are too cold when first put on...at least for me.
I have tested a lot of cooling vests and have settled on this one...
https://www.ebay.com/itm/203252358765?hash=item2f52c8de6d:g:TJkAAOSwzJ9gBlYf&amdata=enc%3AAQAHAAAAoN8btOTIg%2FNRsPL520GWlk1NCVhwidTRXdOyKHNGR7wrNFPdyJP5xZrerAg5PIQZ2qoZyXhmWA5lLon8f8GFEo86F7qHIr9j2EY20223nod48b065b9Idg3ceYShWC5Zj7gisAhxZeNu8N%2Bf24cC21aB9upfikWDQzosdKM9T9uVgFSdWiu7H2OApY3d3NksoqPN4IXKZaCyzeltG8YZdYk%3D|tkp%3ABk9SR6CHndf2YA
It is a bit heavy and bulky, but it keeps me cool even in 95F temps. It comes with 2 phase changing cooling pads. I only use on in the front and get a full 2-3 hours of cooling from one pad. For multiple plates, I wear one pad, keeping the other in an ice chest or simply an insulated bag until needed. I have found placing the pads in the freezer gives me longer cooling times. Despite the freezer temps, the pads "melt" at 54F and are very comfortable. No "freezer burn". Haven't found the reusable limit yet.
The key is to use "phase cooling" or "phase change" products, not ice or evaporative. Ergodyne makes various carrier vests if you don't like the orange look :-) And there are several manufacturers of similar products. Search eBay for sources.
Works great for me. Your mileage may vary.