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The Trewartha climate classification is a climate classification system first published by American geographer Glenn Thomas Trewartha in 1966. It is a modified version of the Köppen-Geiger system, created to answer some of its deficiencies. The Trewartha system attempts to redefine the middle latitudes to be closer to vegetation zoning and genetic climate systems. It was considered a more true or "real world" reflection of the global climate. The changes were seen as most effective on the large landmasses in Asia and North America, where many areas fall into a single group (C) in the Köppen-Geiger system. For example, under the standard Köppen system, Washington (state) and Oregon are classed into the same climate zone (Csb) as Southern California, even though the two regions have strikingly different weather and vegetation. Another example was classifying cities like London in the same climate group (C) as Brisbane or New Orleans, despite great differences in seasonal temperatures and native plant life.