a mild early summer, hot Augusts; it has colorful autumns: Vermont's hills reveal red, orange, and (on sugar maples) gold foliage as cold weather approaches. Winters are colder at higher elevations. It has a Köppen climate classification of Dfb, a temperate continental climate. The rural northeastern section known as the "Northeast Kingdom" often averages colder than the southern areas of the state during winter. The annual snowfall averages between depending on elevation. Vermont is the seventh coldest state in the country. The highest recorded temperature was , at Vernon, on July 4, 1911. The lowest recorded temperature was , at Bloomfield, on December 30, 1933; this is the lowest temperature recorded in New England alongside Big Black River, which recorded a verified in 2009. The agricultural growing season ranges from 120 to 180 days. The United States Department of Agriculture plant hardiness zones for the state range between zone 3b, no colder than , in the Northeast Kingdom and northern part of the state and zone 5b, no colder than , in the southern part of the state. The state receives between 2,200 and 2,400 hours of sunshine annually. New England as a whole receives a range of less than 2,000 hours of sunshine in part of New Hampshire to as much as 2,600 hours of sunshine per year in Connecticut and Rhode Island. Climate change Climate change in Vermont encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Vermont. The state is already seeing effects of climate change that affect its ecosystems, economy and public health. According to the Vermont state government, rainfall has significantly increased in the last 50 years, storms and flooding have increased, and winters have become warmer and shorter. These changes have led to significant impacts on both the winter tourism industry, and a decline in critical agricultural and woodland industries like maple sugaring. The state openly acknowledges and is developing programs that respond to global warming. Vermont was one of the first states in the United States to adopt greenhouse gas emissions goals in 2006. Geology There are five distinct physiographic regions of Vermont. Categorized by geological and physical attributes, they are the Northeastern Highlands, the Green Mountains, the Taconic Mountains, the Champlain Lowlands, and the Vermont Piedmont. About 500 million years ago, Vermont was part of Laurentia and located in the tropics. The