original post by Mentat1123:

Below is my scalable approach that I use to decide what rain protection to take on any hike around the world. I have found that we put a lot of thought into our tents, packs, shoes and even socks but don’t often delve deep into rain gear, so I thought that I would document my process.

Before delving into what rain gear to take, I think the overarching goal of rain gear is often misunderstood. Instead of trying to stay dry, your rain gear selection should be aiming to keep you comfortably warm in the conditions that you face. With this in mind, if you can maintain a comfortable level of warmth, it is actually ok to get wet in certain environments.

Even in the same environment there are a few things that can alter what rain gear we need for each trip.

Length of trip

• The longer the hiking trip is, the more likely you are to encounter extreme weather conditions. This means that on long hikes rain gear should be selected that will keep you comfortable in the expected average, and somewhat comfortable in the expected extreme.
• Short trips, such as day hikes or weekends away, can use the forecast to reasonably predict the weather. This information can mean taking more or less rain gear.

Hiking = Warmth

• It is amazing how warm you can stay when hiking hard. Using this method, you can often get away with less rain protection as you can use your internal furnace to offset the rain that is continuing to draw heat through convection. This knowledge of what you are comfortable with comes with experience.
• If you are naturally a cold person or planning to stop for extended breaks in the rain, you might want to increase the level of protection you bring along.

Below is a scalable checklist that I use to evaluate what rain protection to take on my hikes.

Level 0: No rain gear

Places to use: Usually short day hikes with predictable weather patterns. No rain gear can also be used in tropical climates were the air temperature stays above 75F / 23C, although this does come at some risk.

Basically, I don’t think that anyone can recommend not taking rain gear on an open guide like this, so use your own judgment and local knowledge.

An emergency poncho is the minimum that I take on a hike in good conditions when rain is unexpected. At 1oz (28g) and $1, it is great to keep in the bottom of your bag for that unexpected situation.

Bonus tip: wear the poncho under a wind jacket to keep it from ripping in high winds.

Level 0.5: Umbrella

Ideal places to use:

• Summer in heavy forests – Appalachian Mountains
• Summer in tropical environments with low wind – Central America, SE Asia

Often in hot, humid areas you need protection for comfort from the rain more than warmth. If these area are densely forested a hiking umbrella can work extremely well as your only protection. The trees block out most of the wind that is an umbrella’s kryptonite, and a hot, humid environment often means that ventilation is more desired then staying dry.

I would take an umbrella, wind jacket and an emergency poncho as my rain protection on a mid summer hike of the southern 2/3rds of the Appalachian Trail (Vermont north is a different story).

Bonus tip: an emergency poncho under a wind jacket offers a waterproof layer and almost totally negates the durability concerns of the flimsy product. I know of one person that hiked the whole CDT with this system (not my recommendation).

Level 1: Rain Jacket

Ideal places to use:

• Summer in most mountainous terrains
• Most distance hiking in summer – PCT, AT, Alps, Pyrenees, etc…

This is the standard comfortable entry level for most 3 season conditions and is the go to protection for the majority of hikers.

There are two types of rain jacket material technology;

• 2 or 3 layer breathable jackets (Gore-Tex and eVent)
• Non breathable (nylons such as Pertex in the OR Helium)

Generally, when the jacket is going to be worn more due to a rainy environment, a waterproof breathable membrane (WBM) option of Gore-Tex / eVent with added breathability of underarm zips is used as they offer a good balance between breathability and rain protection. Even with there name, don’t be fooled that they are fully breathable and you will still likely sweat in it, but it will keep you comfortable for a longer period of time the the almost non breathable options.

For minimal use in dry climates or places with only short storms, a lightweight, almost non breathable option made from nylon (e.g OR Helium) is the best option. You will sweat in it and it won’t be that comfortable to wear, but the lower weight and increased packability offsets these discomforts due to the minimal use.

People often expect their jackets to be totally waterproof, but this is almost impossible after a full day of rain. The reality is that adding an extra insulating layer in warm temperatures will cause sweat to build up, even in breathable fabrics.

Getting wet from sweat is not necessarily a problem as the moisture against the skin stays warm while moving and therefore won’t usually cause a significant loss of body warmth. However, once stopped, particular care should be taken to avoid that built up moisture from cooling your core body temperature down.

The more concerning problem is when a jacket loses its waterproof quality. This happens from one of three reasons:

• In Gore-Tex or eVent, the waterproof breathable membrane (WBM) will eventually delaminate. This often happens around the shoulders where the backpack causes the failure through rubbing.
• Microholes in the fabric, and again usually occurs around areas that the pack rubs.
• Jackets can go past their waterproof threshold (eg. 10000mm of pressure), and start to wet out. The first sign of wetting out as a failure method is often moisture penetration along pressure points like the shoulder straps due to them pushing / creating a pressure point on the fabric. It is the same reason as your tent is often damp under your pad. DWR helps to prevent this failure method.

Wetting out of a rain jacket is a greater concern then sweating as a continual leak of cold water that is able to touch the body has the potential to overwhelm a person’s ability to generate heat. When it is cold, hyperthermia is a real possibility if this leaking continues for an extended period of time.

Bonus tip: Rain Jackets can add a lot of warmth when worn to bed at night, as they provide a vapor barrier to trap the heat.

Level 1.5: Poncho

Ideal places to use:

• Wet, humid environments – Appalachians, Tropical areas
• Summer in most mountainous terrains
• Most distance hiking in summer – PCT, AT, Alps, Pyrenees, etc…

This offers a similar level of protection to a rain jacket, but trades off features.

Ponchos

• Keeps upper leg dry
• High breathability
• Vents excess heat
• Requires a wind jacket
• Takes longer to wet out / can be fully waterproof
• Keeps pack dry

Rain jackets

• Keeps lower arms dry
• Poor breathablility
• Retains a lot of heat
• Can poorly act as a wind jacket
• Will wet out in prolonged rain events

The big advantage of a poncho is its natural breathability through ventilation due to it being loose around the body and not from a breathable membrane. This allows for the use of a fully waterproof material such as DCF (formally cuben fiber) to be used successfully. The usability of these fully waterproof fabrics overcomes the problem of wetting out mentioned above, and can offer a huge advantage in sustained downpours.

A poncho also has the added benefit of a backpack cover that is better than the normal ones used.

As with everything, there are a few of negatives with a poncho.

The major drawback of a poncho is due to the ventilated design, as they do not insulate and keep a person warm like a rain jacket. A lightweight wind jacket, or an insulating vest can provide an increase in warmth, but cannot match the layering potential of a rain jacket. Therefore, the majority of warmth has to be generated through walking to maintain body heat and for this reason ponchos are more suited to naturally warm blooded people.

The other two are:

• People often find a poncho annoying in high winds. I personally accept this on long distance hikes as the benefits outway the short time of annoyance.
• A poncho is almost useless on an overgrown trails due to its loose fitting design.

A poncho is my prefered rain protection for the majority of my long hikes as I always overheat with a rain jacket until it is close to freezing. The increased breathability of a poncho keeps me way more comfortable in 3 season conditions over a rain jacket.

I currently use a S2S Ultrasil Poncho on the majority of my summer hikes, with it also acts as my groundsheet. This 15d fabric has resonable durablility and the fabric is much nicer on the skin than cuben.

Level 2: Rain Jacket and Rain Skirt

Ideal places to use:

• Summer in extreme rain environments – Scottish Highlands, SW New Zealand, Patagonia, SW Tasmania
• Fall in high elevation mountain ranges - Colorado Rockies
• Fall in rainy environments – Pacific NW, Northern Appalachians

A rain skirt is not often employed, and is not even known to the general public. But I think that it has a huge advantage of breathability over rain pants to keep you comfortable in long downpours in cool environments. They are also cheap, weigh just over 2 oz / 60g, and can be used as a small ground cloth at camp.

If you are naturally a cold person or the expected temperature is below ~5c and high wind is expected, more protection is required then just a rain jacket but rain pants can be a bit overkill and uncomfortably warm. A rain skirt will be more comfortable than rain pants in these conditions.

I often use a rain jacket / skirt instead of a poncho on shorter trips in high wind conditions, or when I am traveling through overgrown brush. For example, if I have an itinerary of staying above treeline for an extended period of time and I know it will be both windy and rainy, or summer trips to southwest Tasmania or Scotland.

Level 3: Rain Jacket and Rain Pants

Ideal places to use:

• Summer in subarctic environments – Iceland, Norway, Canadian Rockies
• Shoulder season in sub alpine climates – US Rocky Mountains, Sierra, European Alps, Pyrenees, Aussie Alps
• Shoulder season in cold, wet climates – Pacific Northwest, Northern Appalachians, Wales, England
• Winter in mild climates – Southern Appalachians, Many Coastal Walks, many Subtropical areas

Rain pants are great for continuous downpours in moderately cold climates when the expected temperature is approx. 30-45F / 0-7C or lower. Basically, if you think that you will be cold with only a rain jacket, it is time to wear rain pants.

Rain pants come in both breathable or almost non breathable varieties just like rain jackets. They also have the same limitations as rain jackets.

Rain pants are a great insulating layer for below freezing temperatures even in nice weather.

I include rain pants when the expected bad weather is around freezing and colder. I treat them like my jacket and will only put them on when it is actually raining and I need them for warmth.

Level 3.5: Rain Jacket and Rain Pants, with Rain Mitts (possibly Waterproof Socks / Boots)

Ideal places to use:

• Shoulder season in extreme rain environments – Scottish Highlands, SW New Zealand, Patagonia, SW Tasmania
• Winter in mild alpine climates - Aussie Alps
• Winter in cold, dry environments, high deserts – Bolivia, Utah, Northern Arizona

If you suffer from cold hands, rain mitts are a perfect addition to add a surprising amount of warmth to your kit for only an extra 30-45g. Not only are they extremely light, but having a modular system of a rain cover for your hands is far better than the traditional single set of thick waterproof gloves (think ski gloves).

I generally add rain mitts when most of the rain events will be around freezing. They are also great to keep fleece gloves dry in below freezing conditions when it is snowing.

Waterproof socks can be added in these conditions to add extra warmth. I find that I use these in extremely wet environments when there is a lot of frozen rain or when the temperature is below -5C and I need to keep my feet warm. Their durability is terrible so use then sparingly.

Level 4: Rain Jacket and Rain Pants, with Rain Mitts and Waterproof Socks / Boots and a Poncho over the top

Ideal places to use:

• Winter in high precipitation areas – Scottish Highlands, SW New Zealand, Patagonia, SW Tasmania, Appalachians, PNW, Wales, England etc…

This is more of a bonus option and my preferred method to deal with cold, wet conditions mentioned in places above. These places often have freezing rain which, in my opinion, is the hardest weather to counter (followed by wet snow).

The addition of a cuben poncho over the top of a rain jacket and pants adds superb, fully waterproof protection against your rain gear wetting out in a prolonged downpours. It also allows the ability to remain dry with the rain jacket unzipped for increased ventilation.

Instead of taking a heavy 3 layer breathable jacket, a cuben poncho opens the option of bringing a lightweight summer rain jacket and pants. This combination weighs about the same as a heavy jacket and pants, but you will stay dryer the poncho.

I have used this to great success on my Winter Appalachian Trail hike and my Winter Wales and Scottish Highlands Traverses. In Scotland, I stayed dry and warmish in torrential all day frozen rain when my hiking partner sustained mild hypothermia from his standard rain jacket wetting out.

Pepper and Trauma also used this methodology (although a midweight jacket) on their epic Winter PCT Thru Hike Ski.

Unfortunately every persons requirement for keeping warm in the rain is extremely and what works for me might not work for you. The best way to find out is trial and error.

What is your go to rain gear approach?