This International Standard classifies groups of environmental parameters and their severities to which products are subjected when installed for stationary use at non-weather protected locations. Weather protected locations where products may be mounted for stationary use permanently or temporarily are addressed by IEC 60721-3-3, Classification of environmental conditions - Part 3-3: Classification of groups of environmental parameters and their severities - Stationary use at weather protected locations. The environmental conditions specified in this standard are limited to those which may directly affect the performance of products. Only environmental conditions as such are considered. No special description of the effects of these conditions on the products is provided. Environmental conditions directly related to fire or explosion hazards, microclimate within a product, and conditions related to effects from ionizing radiation are excluded. Any other unforeseen incidents are also excluded. The possibility of their occurrence should be considered in special cases. A limited number of classes of environmental conditions is given, covering a broad field of application. The user of this standard should select the lowest classification necessary for covering the conditions of the intended use.