40+ deg on the Atlantic coast of Ireland???
Bought a cheapie lightweight cover from ebay as a temp for my 17' dory on its trailer.
The high side rails meant I needed one of the pontoon boat style.
Less than £19 delivered.
Yes, they are thin & do flap a bit but surprisingly tough.
The edge is elasticated.
Couple of extra ratchet straps over it to help during Dudley, Eunice & Franklin & it's fine - which is more than I can say for several of the neighbours fence panels just up from it!
In its bag it takes up less room than a 12 litre bucket.
This type (mine's in black):
https://www.ebay.co.uk/itm/284627584979
Don't know whether that sort of thing would be worth a try?