United States. Weather BureauOn verso: Dates on which of killing frost in spring falls to 10 per cent -- Dates of which the chance of killing frost in fall rises to 10 per cent -- Number of times in the 20 years 1895-1914 the last killing frost in spring was 10 days or more later than the average date -- Number of times in the 20 years 1895-1914 the last killing frost in spring was 10 days earlier thant the average date.; Includes first killing frost in fall 1914 (inset map), occurrences of first killing frost in fall (chart).; Relief shown by hachures.39 x 59 centimetersJPEGUMN_ALMA:9942876050001701engThe Department (Washington?)PublicAverage dates of first killing frost in fall. : based on records from about 4,000 stations, of which about 700 cover the full 20-year period 1895-1914Maps1916University of Minnesota