At the University of Arizona, where records have been kept since 1894, the record maximum temperature was  on June 19, 1960, and July 28, 1995, and the record minimum temperature was  on January 7, 1913. There are an average of 150.1 days annually with highs of  or higher and an average of 26.4 days with lows reaching or below the freezing mark. Average annual precipitation is . There is an average of 49 days with measurable precipitation. The wettest year was 1905 with  and the driest year was 1924 with . The most precipitation in one month was  in July 1984. The most precipitation in 24 hours was  on October 1, 1983. Annual snowfall averages . The most snow in one year was  in 1987. The most snow in one month was  in January 1898 and March 1922.. How many years apart are the wettest and driest years?