Condensation is caused by warm, moist air coming into contact with cold surfaces. Condensation will more than likely occur inside most tents and awnings, which may sometimes can be misinterpreted as leaking.
There is always moisture in the air when you pitch a waterproof fabric above damp ground, however the situation is made worse by people who are breathing out warm water vapour. When the warm moist air inside comes into contact with the tent, which is cooled by the outside air, condensation forms.
During rainfall more condensation can form due to lower outside temperature and water drops can form and run down seams or fall on internal poles, giving the appearance of your tent/awning leaking.
Main source of condensation:
Ground moisture rising inside your awning.
Your breath. When sleeping at night you will exhale approximately 1 litre of water. This water vapour is then trapped within your tent/awning and will only escape through opening widows, doors or vents into your awning.
Storing damp or wet clothes/shoes inside.
Cooking by gas for ½ hour can produce ½ litre of water.
Tent and awning ventilation is more important than is generally realised - particularly in synthetic materials. Condensation within the tent or awning cannot be completely avoided. Condensation always occurs when you are using your tent, even when there is not a cloud in the sky. The main places for water to form is on the roof poles or roof material this should not be confused with leaks in the tent.
Leave as many ventilation panels open as much as possible, providing water would not be able to get in should it start raining. To prevent ground moisture rising inside tent and awnings a plastic underlay can be put down, these are called footprints and most tents have specific footprints made for them.