Weathering is a special environmental simulation and is undertaken to investigate specific weathering influences on materials.

In the field of surface technology weathering tests are used in particular to determine the weather resistance and longevity of a coating system, for example against UF rays (sun), humidity, temperature and temperature changes as well as industrial emissions and other atmospheric components (e.g. salt). If components are intended to be employed offshore - on the coast or on the sea - , weather resistance is a central quality and assessment criterion.

Whether or not a coating system fulfils the desired requirements with regard to weather resistance can be determined in the scope of various recognised weathering tests. Depending on requirements, the testing may be conducted outdoors with natural weathering (outdoor weathering) or in a laboratory with artificial weathering (rapid weathering).