Typical Alpine Jackets come in what’s called Hard shell, soft shell, and isolated shell, all designed to serve as protective layers in harsh weather conditions—usually at high altitudes, in winter, or during sudden weather changes. The chance you’ll need a Hard shell is the lowest, and for instance, in the Alps, if you find yourself having to wear a Hard shell, it often means you’re in trouble, and more often than not, one Hard shell won’t solve the problem. Some people think they’re invincible just because they own a down jacket—that’s extremely foolish. Wearing one all the time while hiking adds a significant extra burden to your body.
The main function of a Soft shell is to block wind and provide a certain level of warmth. I think it’s mainly suitable for late autumn, winter, or high-altitude areas, while an isolated shell, as the name suggests, doesn’t need much explanation.
All of the above are designed to offer strong protection, but protection comes with trade-offs—it means restrictions, and issues with breathability and heat dissipation can increase the burden on your internal organs and drain your energy. Hiking attire also follows the principle of Occam’s Razor: use as little as possible. If a simple T-shirt does the job, that’s perfect.
During spring and autumn hikes, I usually wear just an inner layer and a fleece top—something like Polartec 100 or 200 gets the job done, providing decent warmth and excellent breathability. For pants, the best option is a single-layer stretch material—you can test by lifting your leg to see if there’s any resistance. These kinds of pants save a lot of energy when hiking.
The above assumes there’s no wind. If it’s windy, or if strong gusts come along with dropping temperatures, then you should go for a soft shell. More commonly, the temperature is okay, but when you’re hiking and sweating in the wind, you’ll feel cold—I think a good choice is a windshirt.
Many people think windshirts aren’t very technical—just a thin layer—and they dismiss them. From my own experience, I’ve found their range of use is actually very broad. When you really start hiking and sweating, even the most breathable soft shell will still feel stuffy unless you open all the venting zippers, but a windshirt doesn’t have that problem—the breathability is in a different league (of course, there are some low-quality brands whose windshirts aren’t breathable). You can comfortably hike in a windshirt. In colder temperatures, you can wear a fleece underneath the windshirt; in warmer conditions, just a moisture-wicking base layer is enough, and this setup also prevents your clothes from sticking to your skin due to sweat. My Peak Performance windshirt got scratched once while hiking, leaving just a mark but not tearing—windshirts aren’t as fragile as you might think. Plus, they’re much cheaper than soft shells, so even if they get damaged, it’s not a big loss. I once wore a windshirt on a sea ferry in Norway, where the deck wind was pretty strong, and I had no issues at all.
In summer, when hiking in forested mountains, I don’t recommend wearing shorts and short sleeves, even if the temperature isn’t low. I’ve been bitten by ticks while hiking in summer—they can cause tick-borne encephalitis, which can be fatal in severe cases, with an incubation period ranging from one week to a month. Fortunately, nothing happened to me after a month. Ticks are found in the Alps and also in forested areas across China. It’s best to wear moisture-wicking long sleeves and pants, and tuck your shirt into your pants—this greatly reduces the risk of being harassed by various creepy crawlies. If you’re taking a break or eating, avoid staying under trees or in bushes; it’s better to sit on a rock in an open area. After your hike, check behind your ears, your neck, arms, inner thighs, and armpits for any bugs.
Finally, and most importantly, use your brain. Weather conditions vary by location, so adjust accordingly. There are no rigid rules or absolutes—don’t waste the small advantage you have as a highly evolved primate.