Daily observations of precipitation and maximum and minimum temperature from the National Weather Service's cooperative observer network collected prior to 1948 were keyed into a digital database. This database includes stations in the nine midwestern states of Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Ohio, and Wisconsin. The primary source used in this project was the publication Climatological Data, which began in 1896. This database provides a substantial enhancement to the National Climatic Data Center's TD-3200 Summary of the Day database, which includes little data prior to 1948. Approximately 2 x 10 7 data values were keyed, increasing the amount of pre-1948 digital data by about a factor of 3 and substantially improving its spatial uniformity. The data were subjected to an extensive set of quality control procedures. It is expected that these data will find their greatest value in applications requiring very long historical records, such as assessments of the risks of extreme events.

Climatologists from the climate centers of 12 states of the upper Midwest contributed temperature, precipitation, and related data for December 1982, January and February 1983. Analyses present the month-to-month spatial anomaly patterns of these parameters. Mean monthly temperatures were much above normal (30-year means) during the three months in virtually the entire region, with maximum magnitudes (+4 to +9°C) extending from the Dakotas to Iowa, and to Indiana (December) and Missouri (January and February). December precipitation was also above normal with anomalies of + 100 mm in much of Missouri, Illinois, extreme southwest Michi-gan, and Indiana. The maximum anomaly was over +250 mm in southern Illinois. January and February precipitation anomalies showed only little deviation from normal. Impacts of the mild winter were generally favorable to consumers in that heating demand was reduced from normal, and particularly reduced from that of the previous year. Costs for urban snow removal were much under budget, as well. The only potentially negative impact was a relatively high survival rate of insect larvae, which is usually controlled by normally colder winter temperatures. The 1982 peach crop of southern Illinois was essentially lost during the 1981-82 winter due to record cold temperatures. The 1983 crop was also lost largely by a late spring frost, even though the winter was one of the warmest on record.

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The review of the climate of the summer of 1983 and associated economic impacts were collated by the state climatologists of 12 states of the Upper Midwest. Their data archives and facilities permitted relatively fast analysis of cooperative station data.Whereas June temperature was near normal across the region, July and August temperatures were generally higher than the 1951-80 normal, with anomalies of +2°C common, and some August anomalies representing a departure greater than 4o. Cooling degree days were 50% greater than normal over about 1/3 of the 12-state area.Precipitation was mixed over the area in June, with the greatest anomalies (ca. 200% of normal) in Illinois, Iowa, Minnesota, and Nebraska. July and August precipitation anomalies were similar to each other, and generally negative. Twenty-five percent of normal precipitation was not uncommon. Indeed, two stations in Nebraska and Missouri recorded no precipitation in August.The impact of high temperatures and low rainfall resulted in substantially less corn and bean yields than expected, but yields of wheat in Kansas, and corn in Wisconsin were greater than last summer. Electrical demand was generally higher than one year earlier, with increases of +15% to +25% common, and 60% greater this July than July 1982 in South Dakota.New climatological records of high temperatures, low rainfall, and number of days with high temperatures were established and re-established during the summer, primarily in the southwestern Upper Midwest.

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