Cool vest of some sort (cooling waistcoat)

[SewRuthieSews]

I've been thinking about making myself a waistcoat with pockets for freezer packs as a way of cooling me down - its due to be over 30 degrees Wed to Sunday here and I'm not built for heat.
Various online things include making cool packs, but I thought I'd do something simple involving a waistcoat with a lot of pockets and just put it on over my clothes and fill the pockets with cool box packs (I have various sizes).

[LeilaMay]

Professional cyclists use ice vests before or after they race in extreme heat 
While going along they use cut off legs from tight filled with ice cubes - down the backs of their shirts. But I guess dripping all round the house isn't going to work?   
Good luck with it - great idea.

[Renegade Sewist]

Slightly off tack cool scarves work really well and are a 10 minute project. Twenty if you're me. There are instructions all over the net. Basic gist is you make a narrow tube,  umm, 30 inches long, fabric cut about 5-6" wide, that is turned right side out and before closing the ends you make small segments near the middle and add  water absorbing polymer granules to each section. You soak it in cold water, the granules expand and you tie it, dripping or not, your choice, around your neck. It cools your blood and you in the process. The granules are pretty easy to get ahold of here, garden centers, craft shops and online. Some florists and craft stores sell them to put in vases with flowers. It only takes about 1½ teaspoons of the granules.

OH used to ride his motorcycle for hours in 40-42C weather using these. He kept a small ice chest strapped on the back of his bike with some ice, bit of water and several spares of these. He'd change as needed.

I use them gardening. Quilting cotton is ideal.

[SewRuthieSews]

Dunno if I've got any of those crystals (maybe in garage).
I have got out an old shower curtain (aqua stripes) which I think could be useful. May have a go today.

[HenriettaMaria]

You can get those reusable gel heat/cool packs from the likes of Boots or elsewhere on t'interweb.  Google 'gel heat and cool packs' and you will get lots of hits.  The benefit of these things is that they mould to your contours, unlike plastic freezer blocks.

[Bodgeitandscarper]

Great idea, but I think whatever cold packs you use, there will be condensation making you/your clothing damp.

[SewRuthieSews]

This morning, I made a basic unlined waistcoat out of a shower curtain and added 4 pockets - 2 at the back, 2 at the front.
Worked well for a blast of cooling for an hour. I didn't mind being slightly damp towards the end.

The cool packs are back in the freezer now for the next session.

[realale]

I've been sleeping with one of these freezer packs at my feet - like a reverse hot water bottle!! I wrap it up so no condensation in the bed and it's resulted in much better sleep.