As someone who sweats a lot, I've found that regardless of the "waterproof breathable" fabric used, I get wet inside the raincoat. So for me the raincoat is very much about staying "warm and wet" and being protected from the wind instead of of being "cold and wet". The so-called breathable fabric do not work for me.
These days the $25 PVC coated nylon rain jacket from the Warehouse is sufficient for me, despite its other shortcomings such as being too short to the body and the hood that requires the use of a truckers cap underneath to allow you to see out.
on of my rainshells is made of Neoshell, one of the most breathable waterproof fabrics on the market, better than event or any gore tex
on a cold windy day with no rain, i can overload it with sweat on a relatively flat walk, it does get less overloaded than other membranes though which can become real sweat fests.
how old is it? a couple of years ago they completely changed the fabric, and it improved the breathability a great deal, they were little better than plastic bags, but the two layer fabrics are worse in prolonged rain because the internal moisture smears over the inside and it won't breathe when that happens, breathable raincoats can only let water gaseous vapour through, water in liquid form won't go through,
Just came off the Routeburn yesterday, where we had 3.5 seasons in a few days. Day 1 to Falls hut was hot summer weather. Day 2 was rain with heavy falls and strong gusty wind over the saddle and along the Holyford face. Day 3 the track was closed by DOC due to a few 100mm of rain (take extra food and something to do as being stuck at a hut for two days gets a bit boring!). Day 4 was cold, clear with a good dump of snow down over the track looking back along the Hollyford face from Lake Mackenzie. My partner and I were very grateful for good gotetex jackets - kept us fully dry but overheating wasn’t really an issue with the gale winds. I bought a marmot precip for our 11 yr old girl and it worked really well for her and was only around $120 or so on sale.
The weather forecasts were actually very accurate - the unpredictable part is having to book so far in advance (we got some of the last spots booking July 2017) and having no flexibility with any of the dates you lock into.
Check those forecasts daily about a week out and use to plan what gear you will take.
It’s a fantastic walk, the snow dump was literally icing on the mountain range views!