Have you ever gotten really cold while wearing a rain jacket and hiking in the rain? It can be really unpleasant and even lead to hypothermia if you let it get out of hand. The best way to stay warm when hiking in the rain, even in summer, is to wear a wicking midlayer under your rain jacket. You may perspire a bit doing this, but it is way better to be warm and a little damp than damp and chilled to the bone. I’ve found that a fleece pullover provides the best midlayer insulation for hiking in the rain and many other experienced long-distance hikers would agree.
Why do you get wet inside a rain jacket? All rain jackets suffer from condensation when the interior is warmer than the exterior when it’s raining because they trap your body heat. That temperature differential is what causes condensation, just like in a tent. Plus a rain jacket, even a highly breathable one, acts as a heat and vapor barrier trapping the warm water vapor that’s generated when you perspire inside.
If you’re just wearing a wet or damp shirt under a rain jacket (in the rain), there’s nothing to prevent the warmth from being sucked out of your body (since it’s cooler outside your jacket and warmer inside). In fact, water (condensation and perspiration) is 25 times more efficient in terms of heat transfer than air, which is why you’ll feel so cold if you only wear a wet shirt under a rain jacket in the rain.
The solution is to wear a midlayer between your shirt and rain jacket that blocks the transfer of body heat to your rain jacket. A polyester fleece pullover or polyester fleece jacket is the best type of garment for this because it is naturally wicking, pulling moisture from your base layers away from your body while maintaining an envelope of warm air around your core. Polyester fleece is also better than wool because it absorbs less water (it’s plastic after all) and dries much, much faster. Polyester fleece is also fairly inexpensive, very durable, and available in different weights so you can dial in the amount of warmth you need for different times of years or climates.
Suggested 100 Wt Polyester Fleece Pullovers and Jackets
- The North Face TKA Glacier Quarter-Zip Pullover ($59)
- Patagonia Micro-D Fleece Jacket ($89)
- Patagonia R1 Pullover ($129)
What about using a down jacket or a synthetic insulated jacket as a midlayer? While these jackets are more popular (and stylish) than lightweight fleece pullovers or jackets, they’re usually too warm to use as a midlayer garment and are best held in reserve to change into when you stop hiking and want to put on drier and warmer clothes. They also absorb a lot of moisture, even if their insulation been treated with a waterproofing agent, and take much longer to dry than fleece unless you have a clothes dryer handy.
For three-season hiking, most hikers will find a simple 100 weight fleece to be effective as a midlayer under a rain jacket when hiking in the rain. A quarter-zip or half-zip pullover or full zip fleece jacket are all good because they provide venting if you feel to warm, but I’d avoid using a windproof fleece because it is less breathable and wicking. Some people prefer a hood and others not, so that is a point of personal preference.Editor's note: Help support this site by making your next gear purchase through one of the links above. Click a link, buy what you need, and the seller will contribute a portion of the purchase price to support SectionHiker's unsponsored gear reviews, articles, and hiking guides.
More Frequently Asked Questions
- Backpacking Clothing – What Should You Pack For the Trail?
- Do You Need Rain Pants for Hiking and Backpacking?
- What are the Strengths and Weaknesses of Trekking Pole Tents?
- Do You Need a Backpack Rain Cover?
- Why Do I Get Wet Inside my Rain Jacket?