One concept that’s tough for beginners to accept is that, when it rains for an extended period of time, you’re going to get wet, seriously wet. If the rain doesn't soak you, the sweat on the inside of your rainwear will.
Forget all your fancy expensive gear when you have to walk in pouring rain for a few hours on a day hike, or several days on a backpacking trip. Your waterproof, breathable rain jacket and pants won’t keep you dry, nor will your waterproof hiking boots/trail shoes. Be prepared.
Your poncho is the most important garment when hiking in the rain through wetlands or rain forests. The robust fabric protects you as you move through muddy shrubland, undergrowth, and open water. You'll wear it a lot on your trek. Get used to it and wear it at home a couple weeks before you go out onto the rain path.
While ponchos are open on the side, capes are closed all round. Some have sleeves which makes swimming possible. Therefore, pick a poncho or hiking cape with sleeves.
When it rains you need a hood or the rain water just runs off your head, down your collar, and into your clothes underneath. Get used to wearing your hood up. If you wear glasses, bring a non-cotton ball cap (baseball cap) to keep the rain off your face. Even though most hiking jackets have a vestigial bill on the hood to protect your face, your glasses will still get spattered without that cap. Put the cap on, then pull the hood up over it.
Breathable rain pants give you good protection from nettles and bugs when you walk through wet vegetation. Zipped pockets keep small things and money handy. We prefer the wide and baggy pants without underwear to avoid chafing. They also double up as swimwear and sleepwear. Comes the morning you can just jump into the water.
Consider hiking with a long rain kilt.
In warm weather it really helps eliminate the chafing and you vent the heat you’re generating.
Your legs also get less wet when you hike in a poncho.
You want to be able to swim in your hiking clothes with a poncho on top as you may cross open water on your trek. Your amphibian hiking clothes should be suitable for swimming and fit well. Your arms must be free to move, either through the open sides of a poncho, or the sleeves of a hiking cape. Try your clothes on in your bath tub and then in a swimming pool. Comfort really matters on wet adventures. Avoid cotton.
When you go for a swim, don't get any dry clothes wet.
Keep them in a waterproof bag for when you really need them.
Instead wear your rain clothes which are already wet.
They make good swimwear and protect your skin from scrapes and bruises.
Some intrepid hikers want to wear nothing under their rain clothes. That's fine as long as your rainwear is lightweight, breathable, and doesn't stick to your skin in an unpleasant way, which may happen when sweat condensates on the inside of cheap rain clothes. Maybe you wear a thin, lose fitting watershirt underneath.
A poncho or rain cape is probably the best choice for warm weather rain walks as it has good ventilation and sun protection. Combine it with thin, unlined rain pants.
We went trekking through the tropical rainforest on Maui, Hawaii, wearing nothing but rain clothes.
The weather changed often from sunshine to heavy rain showers.
We were soaking wet most of the time as we often went through waterfalls, small rivers and lakes.
When the sun came out, our rain clothes dried quickly in the light breeze.
They felt loose and airy, very soft and comfy.
When it is warm enough and/or the rain is light enough, than NOT putting on rain gear may be the smarter choice. The cold/warm decision is easy to make, but the light/heavy rain decision is not.
If in doubt, just get wet and enjoy it. It’s amazing how hard it has to rain to make you wetter than your own “body rain” like sweat.
Fleece clothes will take a long time to absorb light rain or drizzle, before they leak through, also known as "wet out". Fleece doesn't hold on to much water for long, unlike cotton. That's why you can wear it for swimming and still not get too cold afterwards.
If you get cold, put your rainwear on and keep walking.
You soon warm up.
Managing the micro-climate under your rain gear is really the key to all this.
In the summer, my friends and I love hiking in the rain. We ususally go out without any raingear and let our clothes get all wet. Sooner or later we'll cross a small river or go into a lake, so we'll get wet anyway. When the rain soaks our clothes, we can move faster without getting too hot.
The right clothes (not cold cotton) feel really good when wet.
We keep moving and always make sure to have a set of dry clothes and a dry sleeping bag for camp.
In spring and autumn we'll add ponchos
and apply the winter hiking principle of slowing down so that we do not sweat underneath while still dry.