Even though cotton fabrics and tents are breathable, condensation can still occur, especially in damp and cold surroundings with little air movement. This is due to a combination of factors such as air circulation, temperature differences, and humidity:
Tents are typically equipped with vents to allow air circulation. This helps remove humid air from inside the tent and brings in cooler, fresh air from the outside. However, when the warmer, humid air encounters cooler surfaces, like the tent fabric at night, it can lead to condensation. Air circulation and breathable fabric helps to mitigate, but not always eliminate, this issue. Nevertheless, cotton tents reduce condensation significantly.
Nighttime temperatures can be significantly lower than daytime temperatures, especially in mountainous areas or under cold weather conditions. This temperature difference can cause the humidity inside the tent to condense on the inner surface of the tent fabric. This is especially true in particularly humid environments, such as near water or a marsh. Again. Breathable fabric helps to reduce the condensation.
If the tent is placed in a sheltered or quiet environment, it may have less air circulation, increasing the chances of condensation. Stagnant air makes it harder to remove the accumulated moisture inside the tent. This physical principle applies to all materials, breathable or non-breathable.
There will be situations where condensation occur, especially in environments where the air is stagnant (resulting in poor air circulation), damp, and cold. In such cases, condensation is unavoidable, driven by physical principles that are impossible to avoid. This holds true whether you are in a tent with breathable properties or a non-breathable one. Similarly, in a cold cabin with inadequate air circulation, these physical principles will lead to damp walls inside the cabin unless you ventilate or provide some form of heating.
Breathable polycotton helps to reduce condensation considerably. But it is no magical wand that can bend the laws of nature. End users may however help further to avoid condensation by picking appropriate camping-grounds. Pitching the tent close to the water, stagnate airflow and low temperature. You will experience condensation as condensation is bound to physical principles mentioned above. So. Condensation is always a symbiosis between the design of the tent, the fabric, climate, surroundings and the knowledge from end-user.