The short answer is, of course, “Whatever you feel comfortable in”, however most rock climbers will carefully pick their climbing clothes before venturing out to the cliffs and boulders or the local gym. What you wear depends on several variables include:
The weather: What season is it? What’s the weather forecast? Is it hot? Is there a chance of it pissing it down?
The climbing area: What kind of routes / boulders are you attempting? Is it a crack climb? Or a face climb? Is the rock surface either abrasive or smooth?
Rock Surfaces Tears Clothes
Climbing clothes need to be durable, functional, flexible and versatile. Most rocks are abrasive with crystals and edges that can easily tear lightweight fabrics. Tears most commonly occur when climbing cracks or chimneys and sometimes when you reach a course of granite.
Baggy and Loose Fitting Clothes are the Best
Mobility is perhaps the most important factor to consider when you’re trying to decide what to wear for rock climbing. There is nothing worse than having a tight pair of jeans or shorts that cramp your style or squish the never regions for us blokes when you’re high-stepping, stemming or traversing. Climbing clothes must allow you to bend and move without restrictions, meaning baggy and loose fitting clothes are perfect. Three-quarters or shorts which are loose are great in the summer time, jogging bottoms or climbing trousers are good for all other weathers. Try to stay away of multiple layers in the winter if you’re daft enough to climb in the cold, as this will give some restriction as well.
In the summer, dress cool to stay cool
It does certainly get hot in the summer and you need to dress accordingly. Bring and wear the right clothes to stay cool. Lightweight synthetic clothing is great. It protects your skin from the sun and should be loose enough to let the air cool you down. Synthetic fabrics also dry fast after you sweat or if you’re caught in a rain storm; wick moisture away from your skin; and don’t chafe around the goolies and underarm areas. Lots of climbers also wear cotton, which feels good but can be slow to dry. Remember too that light-colored clothes reflect both light and heat, making them cooler than if you wear dark clothes like a black t-shirt.
Your Summer Climbing Clothes
A good summer climbing outfit for most climbing areas includes shorts or three-quarter shorts, a loose shirt like a t-shirt, tank top or sports bra, a billed cap to shield your face from the sun when hiking to and from the cliffs. I made that mistake once and became dehydrated on the way back after running out of water on a summers day. You should carry extra clothes in your climbing pack including a pair of lightweight long pants, a light fleece or long-sleeve top if it gets cold, which in the UK, this happens often in summer evenings. And a compact rain jacket are superb, they come in little pouches and are easy to pack. It is a trick to balance how many clothing items to take when you go rock climbing, but it is better to be prepared by bring a few extra articles of clothing so you can change if you get wet.
Warm Climbing Clothes for Cool Weather
When you’re climbing in much cooler weather, you need to both wear and take extra, warm clothing. In some seasons, the weather quickly changes so you have to be prepared for the worst. It’s important to bring extra clothes that provide insulation from wind, rain, and snow, and also keeps you dry. Most outdoor clothing manufacturers sell lots of different kinds of pants / bottoms, base layer shirts and jackets for rock climbers.
Avoid Cotton Clothing
You should avoid cotton clothing in cold and wet weather. Cotton absorbs water and then sucks heat from your body when it’s wet, which can lead to hypothermia, a chilling of the body’s temperature. Cotton is also slow to dry so you will often have a damp cotton layer resting against your skin. Save your cotton clothes for summer climbing or dry conditions.
Here is also short video about what to bring to the wall or crag :