Outdoor Research Helium II Rain Jacket

Ultralight Rain Protection

When it comes to outerwear for rain protection, striking a balance between waterproofness, breathability, and weight is one of the classic struggles of the outdoors lifestyle. This is the realm of high tech fabrics that usually have a narrow window within which they function well, but it’s a window that can be hard to work within in the real world. Outdoor Research has a pretty solid reputation in this sector of outerwear, so they were as logical a place as any to start when looking for an ultralight rain jacket. We’ll take a look at the Helium II which is one of their most popular offerings, and easily found at most outdoor retailers.

Specs at a Glance

All specs as claimed unless *noted otherwise…

  • Fabric: Pertex® Shield+ 2.5L (30D)
  • Hydrostatic Head: 20,000mm
  • MVTR: 25,000 g/m²/day
  • Weight: 6.2 ounces (176g) on my scale (size medium)
  • MSRP: $159
The OR helium II
The OR helium II


The Helium II is a nice looking, close fitting, and lightweight rain jacket. The fabric is very thin and super light, which is great for packability both in terms of low bulk, and overall weight added to the load. However, it’s not going to stand up to abuse well. To put that in context, it’s going to be susceptible to granite rash and punctures from bushwhacking. The hood is a very nice fit and looks to have enough clearance to get over a climbing helmet (I can’t confirm). It also features a brim in front and a draw cord to cinch it close to the head, which helps keep it in place in the wind. The zipper on the chest is just a pocket, which is ok for a folded map (etc…) but not really a needed feature. I’m tall and thin (6′-2, 155 lbs) and the medium fits me pretty well. The arms are plenty long, which was a nice surprise, however the torso could be a bit longer. It can be layered over a typical down jacket, however my down jackets are about 2 inches longer in the torso, so I’d have to tuck them up inside and use the bottom draw cord to keep them from slipping out – a less than ideal solution.

In the Field

I’ve owned the jacket for about a year now. I’ve used it on some longer backpacking trips in the Sierras as well as over our record-rainy winter here in Marin. Rain jackets are something I have somewhat of a bad history with. I have not met one yet that didn’t have it’s shortcomings. I only say that to make it clear that I don’t believe there is an ideal rain jacket out there (yet). The Helium II is super light, so it’s well suited for ultralight backpacking adventures, as well as trail running. Let’s talk about the backpacking first.

Backpacking in SEKI
Backpacking in SEKI

For trips where you’d expect to be hiking for several hours in steady rain, this is not the best choice. Pertex Shield+ is a nice fabric, and it’s amazing what it can do for such little weight penalty, but after a couple hours of steady downpour you can expect it to start wetting thru. If you tend to run hot while you hike, or move at such a pace that you’re exerting yourself, it may also prove to be less than ideal. Despite the breathability claims of the material, it tends to feel like being in a sauna during times of exertion. To be fair, this is one of those points that any rain jacket I’ve encountered fails at. This brings us to running…

Trail running in the Helium II I find it to lack breathability sufficient to vent out all/most of my perspiration and heat. Again, I would be shocked if there is any jacket/material up to this difficult task. Other jackets in this class include the Montane Minimus and Inov8 Stormshell HZ. They all perform about the same. So, it keeps the rain off for an hour or two, but you’re getting wet from your own sweat… where’s the sense in wearing a rain jacket while running then?

Trail Running in Marin
Trail Running with Sandra D in the Marin Redwoods

This is what I’ve found: It takes a while to generate enough sweat to get really soaked, and some of it is being vented off. Meanwhile the jacket is also keeping some heat in. In tropical climates it’s probably a bad choice to wear a rain jacket while running, but in cooler wet climates it can really help to maintain a comfortable body temp on longer runs (especially if there’s a breeze). On shorter runs it’s possible to come back fairly dry… unless you’re a profuse sweater, in which case you’ll be well marinated!


  • Pertex Shield+ is one of the better fabrics suited for light rainproof gear.
  • The light weight is great
  • Lots of snazzy colors (super important)
  • Hood stays in place in wind and while running
  • Outdoor Research customer service (see below…)

Not So Much…

  • The shock cord on the hood broke internally. OR did replace the jacket for me though.
  • Torso length could be longer, or at least extended to cover seat of pants
  • No pit zips to help vent moisture and heat
  • Wets out after a couple hours of rain

Famous Last Words

This jacket strikes a good compromise between performance and weight. There are jackets that weigh twice as much but probably don’t perform “twice as well”. For running or occasional use while backpacking it’s a pretty nice piece of kit to have along. It fits easily into a backpack or running vest and the minimal weight penalty means you don’t have any hard decisions to make when it comes to bringing a rain jacket or not. I wish it had some pit zips to help with body temp regulation and to vent some moisture out, but otherwise I’m happy with the Helium II and will continue to use mine until something better comes my way! Hike It. Like It.

Jacob D Written by:

Jacob is the head honcho, wearer of many hats, and modern day berserker here at Hike It. Like It. When he's not out hiking or running the trails you'll find him operating in full capacity as a Super Dad and chipping away at a degree in Kinesiology. This guy likes to stay busy. Follow on Strava

One Comment

  1. March 6, 2017

    In open country, helmet compatible hoods are a liability as they tend to blow off as soon as I turn into the wind. Some, but not all, will stay in place if I haul hard on the volume adjusters.

    Also, hard volume adjusters mean the hood cannot be raised if sleeping in the jacket on an unexpectedly cold night as lying on the volume adjuster is very painful, particularly for those of us who are bald.

    I agree with your comments on Pertex Shield. It’s thinness worried me when I first started using it but it is tougher than it looks.

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