For Rock Climbing, dress in layers. Clothing for the gym climber is simple: shorts, sweats, tights, anything that is easy to move in. Gyms are often cold, so a sweatshirt or sweater is nice to wear until you are warmed up.
Remember that you will be wearing a harness and that it is best to keep your waist area neat and visible. Super baggy clothes or large shirts that cover up the harness are not recommended. ‘hick shirts in and clothing under the harness, if possible.
Clothing for outdoor sport climbing is similar, but add a jacket and hat for weather protection. Sport climbing outside is characterized by periods of intense climbing that generate plenty of warmth, followed by long periods of standing around belaying or resting. Be prepared to pull on a jacket or even warm-up pants to stay warm in between climbs.
Longer traditional climbs require more specialized clothing. It is entirely possible to be caught in changeable, severe weather high on a climbing route. An hour of cold rain can turn a pleasant outing into a survival epic.
Choose synthetics for clothing on longer traditional climbs because they do not absorb water, are warm when wet, and dry quickly. Always have a rain parka and possibly rain pants, a hat, and an extra warm vest or sweater accessible in a pack if the forecast is questionable.