What Running Jacket Do You Need? Running Jacket Buyers Guide

As soon as the temperature drops, the wind gets up or it starts to rain, you’ll wish that you chose the correct jacket. Helping you choose the correct jacket is the sole focus of this guide! How much protection you require from your jacket will depend on the conditions you are going to be running in and whether you tend to personally ‘feel the cold’ or not.

A good running jacket needs to protect you from the weather on the outside and be as breathable as possible so that you don’t overheat inside. Traditionally, the rough rule of thumb is that the more waterproof the jacket the less breathable it is. Selecting the correct level of protection for both the length and type of runs you are doing, as well as considering how hot you usually feel in jackets, will make you more comfortable whilst running.


Wind Resistant/Windproof

When the wind is blowing whilst you are sweating you get cooled down by the wind. It’s no fun when you feel like that wind is coming straight through your long sleeved top or jacket and you’re struggling to keep warm. A wind resistant jacket or smock will protect you from the wind and warm you by trapping air between your body and the jacket. These jackets are usually made from a tightly woven nylon. They are the most breathable of all jackets. They are very light and packable.

Is This You?

“It’s dry & windy and I got a bit too cold last time I went out. I wish I could take my duvet!”

The ideal jacket/smock for these conditions is a wind resistant one. They are very light & packable and will easily tie round your waist and go unnoticed, or fit into a pocket of your shorts or tights. You might set off on a cold winter’s morning run with the jacket on and then just take it off when you’ve heated up. Alternatively, these are great for carrying with you and popping on once feeling exposed or getting cold. These jackets focus on packability, so they often don’t have pockets or if they do, they are quite small.

Water Resistant

In light rain or snow a water-‘resistant’ or ‘repellent’ treatment on the jacket will let moisture bead/run down the jacket and not penetrate the material for a period of time. These jackets are not as breathable as a wind resistant jacket but usually more breathable than a fully waterproof jacket.

Is This You?

“It’s raining or drizzling but I’m going to head out anyway and am going to be running for up to an hour or so. I’m not using some rain as an excuse!”

Great for the regular British mild-yet-rainy day! A water repellent jacket will do the job well in this instance for up to an hour or so. They are more breathable than fully waterproof jackets, which means that you won’t get as hot in the jacket. The rain will bead down the material, which stops it from soaking into the jacket. If you are out for a little longer or the rain is particularly hard then you might find that some rain does get into the jacket. However, as you warm up and sweat on the inside of the jacket and have invested in a couple of good base layers that are designed to keep you warm when it’s damp, then you will still be comfortable.


Usually jackets that are waterproof have a membrane that is designed to let sweat out, whilst not letting water in. The seams are taped to prevent water coming in. The level of waterproofness and breathability does vary but all jackets of this type will be more waterproof than a water repellent jacket.

Is This You?

“It’s Sunday morning, my long run day, I can hear the rain bouncing of the windows and I’m going to be out for a good few hours. It looks terrible, but I’m up for it!”

For the conditions described above you need a quality, fully waterproof jacket. This is also the answer to a common question; what jacket do I need for an ultramarathon or trail/fell race? The rules of these events usually stipulate that the jacket should have taped seams (taping over the seams of the jacket means rain can’t get in through the stitch holes) and a hood.

Waterproof jackets usually have a membrane inside the jacket. This is essentially a mesh filter. Fortunately, sweat droplets are smaller than droplets of rain. That means that the membrane can allow perspiration to go out but stop rain coming in. How effective a material is in keeping the rain out is measured by the Hydrostatic Head. This is how much water can be stacked up onto the material before the rain droplets start to get forced through the holes.

Hydrostatic Head – How Waterproof A Jacket Is

A jacket is considered to be waterproof if it has a hydrostatic head of 10,000mm or more and breathable if it has an MVTR of 10,000mm or more.
The waterproofness varies from jacket to jacket. How waterproof you need the jacket to be depends on the time you will be out and how bad conditions are likely to be. Below is a rough guide.

10,000mm HH: Great for spring/summer use in the hills & mountains, where weather is changeable, or drizzle/light rain around town. If you are in heavy rain for a prolonged time then you will probably find water makes its way inside.

20,000mm HH: The most common level used and required by most runners. Great for winter use in the hills/mountains when the weather starts to fight with you. The jacket will resist heavy rain for a pro-longed period of time when new and if the beading is rejuvenated from time to time.

30,000mm HH: This is currently the highest level of waterproof protection. Protection for that horrendous weather on your long days out. As with all waterproof jackets they still need to have the beading rejuvenated from time to time.

The other thing that affects how waterproof a jacket is when you’re running for a long time is how many layers of material make up the jacket. Running jackets are designed to breathe well and be light. They don’t have as many layers as a hill walking jacket would have, which makes them less waterproof but more breathable. The really light jackets will have a single layer. If you’re out in the hills for a long time, you’ll need 2.5 layers.

Moisture Vapor Transition Rate – How Breathable A Jacket Is

How effective the jacket is at breathing is measured by the Moisture Vapor Transition Rate.  It is worth considering how breathable you need your waterproof jacket to be. If you tend not to overheat when running in a jacket, then this is less of an issue. From experience we have found a lot of men find that they get a few miles down the road and they are as wet on the inside as on the outside! In this instance breathability is very important.

On a cold day 10,000 MVTR will be fine on easy runs for a lot of runners. 20,000 MVTR is probably the most popular. If you find you easily overheat in jackets then you need to buy the highest level, which would be 40,000 MVTR. N.B. The Gore-Tex SHAKEDRY, which Gore don’t give an MVTR figure for, is the most breathable waterproof we have ever used.

Don’t Forget Your Base Layer!

The other important thing to realise is; how comfortable you will feel running in a jacket is dependent on what you wear underneath it! Summer running t-shirts are designed to keep you cool in the warm and a basic cotton t-shirt that you would wear casually will get wet and can feel cold.
The best thing to use is a quality base layer that will keep you warm even when it’s wet. Helly Hansen are great, Inov-8 too.

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