Holidays in September: 5 things I don't go hiking without. Especially in autumn!

September is the best time for a trip to the mountains. The trails become deserted, the sun no longer burns so mercilessly, and the air becomes even clearer. However, there is another side to the coin: treacherous temperature swings.

During the day, on an ascent, a light T-shirt is enough. But as soon as the sun disappears behind the ridge, the temperature drops drastically, and the cold wind penetrates to the bone. If you are wearing clothes that retain moisture (sweat after a full day's hike), it's easy to catch a cold.

Here's what protects me from this, my ranking of 5 accessories for September chill that ensure comfort in the mountains.

1. Place #1: All-season thermal underwear

Why is it number 1? Because it works close to the body – where all thermoregulation begins and ends.

September requires special purpose clothing. Classic cotton absorbs sweat like a sponge and stays wet for a long time. When you stop for a rest, you'll immediately feel it - like a cold compress on your back that quickly lowers your thermal comfort. I don't go to the mountains without my beloved Icebreaker longsleeve - I always have it with me when skiing, running, and on via ferratas.

What instead of cotton? Choose thin thermal underwear made of merino wool, ideally without the addition of synthetic fibers, such as polyamide or polyester, but with a small admixture of elastane, which will provide the "second skin" effect.

How does it work? Wool wicks away moisture on an ongoing basis during hiking or climbing, preventing overheating. When you slow down, it traps a micro-layer of warm air next to the skin, but not moisture. That's the whole difference!

A long-sleeved thermal shirt takes up next to no space in your backpack, and after sunset, you'll definitely appreciate having it!

2. Place #2: Socks with merino wool

Cold always attacks from the feet and head. My feet are always cold, so I'm obsessed with socks. And I know that the warmest waterproof jacket won't save my thermal comfort if I let my feet get cold.

Why merino? Merino wool has amazing properties - it keeps you warm even when wet, and it doesn't absorb unpleasant odors (which is important on a multi-day trip without access to a washing machine).

Effect: Dry, warm feet and zero blisters after a full day's walk.

3. Place #3: Light longsleeve or sweatshirt with a stand-up collar and zipper (Half-Zip)

For the second layer in our ranking, we recommend a zip-up sweatshirt or a thermal shirt of slightly higher grammage, necessarily with a zipper at the neck. Ideally, it should contain wool, because this will not only provide warmth but also ensure air permeability and ventilation. And in case of rain, it will prevent you from getting cold even when wet.

My beloved zip-up hoodie is from We Norwegians. This Scandinavian brand was founded over a decade ago, and its founders are avid skiers with experience in the clothing industry. The result - phenomenal design and natural fibers, clothes that keep you warm while trekking and look great. It's hard not to love their products!

Why is a zipper at the neck the key to success? It's the simplest and most precise "thermal zipper." Going uphill? Unzip the collar and quickly ventilate your body. Entering a shaded forest or the evening wind starts blowing? Zip up the collar all the way to your chin, protecting your sensitive neck from drafts.

4. Place #4: Multi-functional neck warmer (Buff) made of merino wool

A small, inexpensive gadget that should be in every backpack pocket from September to May. I even take it with me in August when I go to the Polish seaside or the Bieszczady mountains. And almost always when running. Sometimes it protects me from the wind, and sometimes from air conditioning, which, although a blessing in hot weather, can affect my tonsils.

Versatility: You can wear it as a scarf, protect your sensitive sinuses during a walk by the sea on a windy day, or as a headband over your ears.

Its biggest advantage is its weight: It fits in any pocket and weighs tens of grams, and if it's made of merino, even less. When the temperature drops by 10 degrees in an hour in the evening, it's good to have such a neck warmer on hand.

5. Place #5: Leak-proof thermos

Thermoregulation is not only about what you wear but also what you fuel your body with from the inside.

Hot ginger or lemon tea drunk with a view of the mountain peaks at dusk can warm up blood vessels faster than any sweater.

Combine a warm drink with a well-chosen first layer (thermal underwear), and no September evening will force you to return to your room earlier.

I have tested many cups, and my favorite is this one - Fellow Carter. Nina Czarnecka once recommended it on her IG (Blimsien). What convinced me is that it doesn't absorb odors. So you can drink coffee in it in the morning and tea in the evening, and one doesn't taste like the other :) Plus, they really keep both cold and hot for a long time. And they are incredibly light and pretty.

Quick guide: How to dress for September mountain trips?

Time of day / Activity	Phenomenon	What to wear?
Sunny day on the trail	High effort, moderate temperature	Thin thermal T-shirt (sweat wicking)
Break / Mountain peak	Wind, rapid cooling	Thermal T-shirt + light windbreaker/sweatshirt
Cool evening by the campfire	Temperature drop, no movement	Thermal underwear (base) + sweatshirt + jacket + neck warmer

September does not forgive clothing mistakes – a cotton T-shirt after a full day's hike becomes a cold compress as soon as you stop for a rest.

The key to a successful trip is layering and investing in good first layers that ensure your skin stays dry and warm. Pack a set of thermal underwear, good socks, and a neck warmer – and the September chill will merely be a backdrop to beautiful views!

Looking for the perfect underwear for your September trip?

Check out our merino collection and choose a set that will ensure your comfort in all conditions!