The historic precipitation data is made possible by a network of observers
from around the state.  Each observer volunteers their time and
effort to taking daily precipitation measurements.  Some records may be 
longer than others while some may have more complete days.  

Here are some numbers that might be useful:

-9.99 = No data was recorded that day
-1.00 = Trace of Precipitation
  707 = Accumulated Days (The First in the series is indicated by -9.99
        and the last day is the accumulated total)
  808 = Original Observation was measured in inches of snow and has been
        modified to get total precipitation (1 in. of snow = 0.10 of
        Precipitation)
  606 = Day was left blank and observation was changed to -9.99
  505 = Time Periods contain two cards with different precipitation
        values, second card is the default (may contain note of
        explaination)

Please direct all questions to State Climatologist, Dr. Daniel Leathers:

          Office of Delaware State Climatologist
          210 Pearson Hall
          University of Delaware
          Newark, DE 19716
          E-mail: leathers@udel.edu
          Phone: (302) 831-8764