I've spent much of my long life searching for the ideal coat that will suit all conditions. I can't recall them all but do remember using the following.-
Garberdine raincoat: Hot, not waterproof, not warm, takes forever to dry, hard to carry and pack. No idea of price as Mum bought it for me. Hated it when made to wear it up Helvellyn in the 1950s.
Oilskin cycle cape Tore easily and replaced with plastic version. Cheap and portable but with drawbacks of poncho without their advantages, Bright yellow!
Army gas cape, stuck together when rolled in pack. Smelly. Issued so glad I didn't pay for it.
Ex-navy duffel coat: Warm, surprisingly water resistant, impossible to pack and hard to carry Cheap and flogged it to a student of my wife's about 30 years later. Moths were very upset about losing food source.
Pak-a-mac. Plastic cheap, windproof and fragile. Got wetter from condensation than rain.
Greenspot cotton double skin "windcheater" wiindproof, water resistant when newly treated with "nev".Quite liked this and sorry when it wore out. Modified it extensively, by adding pockets etc and experimenting with waterproofing.
Nylon raincoat: light, easily carried and packed windproof, waterproof. Some ******* pinched it from my parked scooter in Portsmouth in1960.
Corduroy jacket. Second hand two sizes too large. Comfortable. Not wind or waterproof took weeks to dry out. But really fancied myself in it. Could have been right as met wife when wearing it in 1961.Probably the only jacket I've ever bought for appearance rather than function.
Navy foulweather oilskin modified to jacket length and carried all across Europe in 1966. Water and windproof, very cheap but a bit heavy.
Polyurethane coated cagoules .Several of these, waterproof but not condensation proof most had to be replaced as coating wore off from inside.
Goretex!! first of several. Made by Berghaus, If only it had lived up to the advertising claims. Never have worked out whether water was coming from inside or outside.
Several others with claims to being the perfect answer to the condensation problem. None was. Most came unlaminated after a time, and appeared to be OK but suddenly became permeable usually unexpectedly in the middle of a wet-weather trek in Wales or Derbyshire.
Paramo cascada. Have had this for years now, reproof it at least every years, Wind and waterproof and warm. Bit heavy and hot for summer, but saves carrying and extra warm layer. Very expensive to buy, but when worked out on cost per year of use, much cheaper in the long run.
Experience has taught me that a shell over layers is far better than a warm and waterproof jacket. I hate using waterproof over trousers, but keep a light pair in the pocket of my Paramo.
I'm still looking for the very light and packable water and windproof outer shell that I can snuggle into when it's howling with sleet and still feel dry and snug. It has to be roomy enough for a couple of insulating layers without being too big for summer use on its own. Oh, and it has to be a dull subdued colour- I don't like to be easily seen!