NBC/hazmat suits for how weather

Since you have not seen any examples that is a good indication that they are not commercially available. I have never seen
such a product and the reason is clear. They require a refrigeration unit. For cold weather it is all about retaining the heat
so layering of clothing and the right clothing material do the job. Thus you have products of all types all of the place. Carrying
a refrigeration unit even if it is light still requires a power source. And that breaks the bank.

One of those portable fridge type jobs can likely be installed in a convenient backpack, but you are not going to be able to
carry a wall socket around you. Battery technology is woefully primitive and thus heavy since the stored electrons per
atom does not exceed 2. Carrying propane or some other combustible gas or liquid to run a thermally-driven cooling unit
is not all that practical either.

Your question is actually very relevant. We are headed for a climate regime where a large part of the tropics will have wet
bulb temperatures high enough to cause mammal mortality since the evapourative cooling no longer works. We already
see such incidents in India and elsewhere, when there are temperatures reaching 50 C coupled with high relative humidity.

Sorry I don't know of any hazmat suits like that... or any hazmat suits at all, but if I were you I would be looking at sports shops and local sports centres and universities... quite often they have water cooled vests for athletes working in hot regions that just pumps cold water through clothing for upper and lower body... it might come with a small backpack with a body of cool water to cycle through perhaps with an opening big enough to drop a few ice cubes into every hour or so... it is not like they are trying to drop the temperature to keep frozen meat frozen... sometimes when it is hot an outer insulation layer and water that is a few degrees colder that the air around you can help a lot.

I have a santa suit that is inflatable that comes with a small USB powered fan... that you attach to the shell and it sucks air into the suit which inflates it with cool air... but obviously that wont be an option with a hazmat suit... it could be used to cool the water as it goes back into the clothing though... inside a backpack...



(note it comes with a battery pack for AA batteries but the connection is a USB cable so I just use my power bank for my phone to power it... fan and batteries bottom right above)..