Waterproof Jacket Guide | How To Choose A Waterproof Jacket For This Years Hiking Season

Buying a great waterproof jacket this year is not as easy as you might think.  The problem with buying a waterproof jacket is getting the balance correct between the right amount of waterproofness with the right amount of breathability.  

In an idea world, you would simply buy a plastic jacket that offers 100% waterproofness.  The problem with this, especially for hiking is that you'd end up soaking wet as the jacket would not release any of your perspiration.  If you go the other way, you'd end up with a jacket that's not waterproof, but totally breathable.  Not what you want.  

Breathability Vs. Waterproofness

In an ideal world, we're looking to balance the breathability against the waterproofness against what you're using the jacket for.  If you're hiking the summer across low level hills in the Exmoor National Park as example, it's more than likely you're going to want a day-jacket that offers more breathability rather than waterproofness.  

Yes it does rain in Devon, but it never gets really cold.  You're going to want a waterproof jacket that will keep you dry, but offer breathability so you sweat can escape as you walk across the Hills.  If you're hiking in the Scottish Mountains in the Winter, it's likely that you're going to sacrifice some breathability to make dam sure you stay dry.  There is nothing that will make you cold quicker, than getting wet in the mountains.

Waterproof Jacket Ratings

How waterproof a jacket is will depend on its waterproof rating. The higher a jacket’s waterproof rating, the longer the fabric will remain waterproof.   One point, never trust a manufacture that tell you their jacket is 100% water-proof - It's not. Unless it has been designed with taped seams it will start to leak at some point.  

All waterproof jackets are rated according to their resistance to water. Typically there are five key ratings that you should be aware of and take into account if you're buying a waterproof jacket;

Below we have produced a table showing the waterproof rating of clothes and realistically what type of weather they can stand up to. In the UK, the British standard for water proof jackets is 1,500 mm. Anything less and the shops cannot market them as waterproof, however the honest answer, if you're in the countryside with a 1,500mm jacket and it starts raining, you're going to get wet. 

The lowest rating is water and snow resistance only and can cope only with light rain. The highest ratings are for extreme wet weather and ideal for water pursuits such as canoeing and sailing. In accordance, factories test each jacket using a hydrostatic head test that tests how much water the outer shell of the jacket can hold before it leaks through to the inside.

Waterproof Rating (mm)

Water Resistance Provided

Usable Conditions

0 - 1,500 mm

Very litte

1,500mm is the legal requirement in the UK, but you can hardly call it waterproof.

1,501 - 10,000 mm


The top end of this scale get a fully waterproof jacket that will keep you dry in everything but the heaviest of rain.

10,001-15,000 mm


When jackets are above 10K, we're into the range where they're totally waterproof in even the heaviest of rain

15,001-20,000 mm

100% Waterproof

Above 15K and we move into dry-suit territory.  The only way water get through a dry suit top, is your seal start to leak.

20,000 mm+

Very Good

Above 20K and we're talking about dry suits that deep sea divers wear to work at the bottom of the ocean.


The second number you're going to be interested in if you're looking to buy a decent waterproof jacket this year, is it's breath-ability. Again this is a numerical rating, expressed in (g).  In very simple terms, it's the number of grams of water vapor that can be passed through the fabric in period of time.  Basically, the larger the number, the more breathable the fabric is.  

Breathability Rating (g)

Breathability Provided

Usable Conditions

0 - 3,000 (g)

Very Little

There's no legal requirement in the UK, however anything below 3K grams is basically not breathable.

3,000 - 5,000 (g)


5,001- 13,000 (g)


13,001-18,000 (g)


18,001+ (g)

Very Breathable

Types of Water Proof Jacket

There are 4 main types of water proof jackets; two layer water proof jackets, three layer water proof jackets, 3 in 1 water proof jackets and pakka water proof jackets.

  • A two layer waterproof jacket, the most common of the four, has, as the name suggests, two layers. The outer layer or shell prevents the rain from soaking into the coat and the inner layer or liner helps to maintain the outer part by creating a shield between the shell and the owner's sweat and movement.
  • A three layer waterproof jackets contains one extra layer – another protective lining to safe guard the jacket from torrential rain.
  • A 3 in 1 water proof jacket doesn't have the protective layer of a 3 layer water proof jacket, but does have a fleece on the inside that will keep you warm when the temperature drops.
  • A Pakka jacket is a foldable lightweight waterproof jacket that you pack away in it's own small pouch and small enough to put in the side pocket of your bag. It may not be as fully water proof as the others, but it is perfect in changeable weather.

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