Arm sleeves can be worn in various weather conditions, but their effectiveness and comfort may vary depending on the temperature and humidity. In cooler weather, arm sleeves can help keep the arms warm and prevent muscle stiffness and soreness. In hot weather, arm sleeves can help wick away sweat and provide some protection from the sun. However, wearing arm sleeves may cause discomfort or overheating if the weather is very hot and humid. It's essential to choose arm sleeves made from breathable, moisture-wicking materials and to stay hydrated during exercise in hot weather. Overall, arm sleeves can be a valuable accessory for runners and athletes in various weather conditions. Still, it's essential to consider the temperature and humidity levels and to choose the right type of arm sleeves for the conditions.