NOAA U.S. Climate Normals

The U.S. Climate Normals are a large suite of data products that provide information about typical climate conditions for thousands of locations across the United States. Normals act both as a ruler to compare today’s weather and tomorrow’s forecast, and as a predictor of conditions in the near future. The official normals are calculated for a uniform 30 year period, and consist of annual/seasonal, monthly, daily, and hourly averages and statistics of temperature, precipitation, and other climatological variables from almost 15,000 U.S. weather stations. <br/><br/> NCEI generates the official U.S. normals every 10 years in keeping with the needs of our user community and the requirements of the World Meteorological Organization (WMO) and National Weather Service (NWS). The 1991–2020 U.S. Climate Normals are the latest in a series of decadal normals first produced in the 1950s. These data allow travelers to pack the right clothes, farmers to plant the best crop varieties, and utilities to plan for seasonal energy usage. Many other important economic decisions that are made beyond the predictive range of standard weather forecasts are either based on or influenced by climate normals.

美国气候常态数据集是一套庞大的数据产品集合，为美国境内数千个地点提供了典型的气候条件信息。常态数据既可作为衡量今日天气与明日预报的标尺，亦能预测近期气候条件。官方常态数据基于统一的三十年周期进行计算，包含来自近15000个美国气象站的年度/季节性、月度、日度和小时度平均气温、降水量以及其他气候变量的统计数据。美国国家气候数据中心（NCEI）每十年根据用户社区的需求以及世界气象组织（WMO）和国家气象服务（NWS）的要求，生成官方的美国气候常态数据。1991-2020年美国气候常态数据是该系列首次于20世纪50年代产生的十年期常态数据中的最新数据。这些数据使得旅行者能够携带适宜的衣物，农民能够种植最适宜的作物品种，以及公用事业公司能够规划季节性能源使用。许多超越标准天气预报预测范围的重要经济决策，要么基于气候常态数据，要么受到其影响。