environmental disposition climate The disposition of an environmental system, particularly those influencing atmospheres, to manifest a cyclic pattern of weather over time. The current alignment of "climate" under BFO:disposition is drawing from its very useful etymology (Ancient Greek klima, meaning inclination). The climatic conditions currently used to axiomatise biomes (polar, tropical, etc) may be better placed under this class. Climate is commonly defined as the weather averaged, or otherwise summarised, over a period of time much longer than the duration of any phenomenon that constitutes weather. The standard averaging period is 30 years, but other periods may be used depending on the purpose.