Delaware Annual Rainfall and Climate Data, see below for individual cities 

 Delaware Average Annual Precipitation

Delaware city precipitation totals

City

Avg Annual Precip

Avg Annual Snow

 Avg # days of Precip Avg # thunderstorm days Avg # hail days Avg # severe thunderstorm watches per year Avg # tornado watches per year # of tornadoes reported in county, 1960-2010
Dover 44.66 15.0 114 28 1 2 8 18
Wilmington 42.81 21.4 116 29 1 2 10 20
  • Delaware Annual  Precipitation Average - 45.68 inches, 16th wettest in U.S.
  • Delaware Tornado Average - 1.2 per year, 44th most in the U.S.
  • Largest reported Tornado in Delaware from 1950-2011, 10/18/1990 - 430 yards / .24 miles wide
  • Month with highest number of reported Tornadoes in Delaware from 1950-2011, June - 8 tornadoes
  • Average time of occurrence of reported Tornadoes in Delaware from 1950-2011 - 3:39 pm
  • Delaware Annual Lightning Density - 8.0 flashes per square mile - 22nd highest in U.S. 
  • Record Driest year in Delaware from 1895-2012 - 1930, avg precipitation 28.29 inches 
  • Record Wettest year in Delaware from 1895-2012 - 1948, avg precipitation 62.08 inches 

Delaware Precipitation Data

  • Driest location ranked by lowest annual precipitation: Middletown, northern Delaware, 41.58"
  • Wettest location ranked by highest annual precipitation: Wilmington Reservoir, northern Delaware, 49.02"
  • Snowiest location ranked by highest annual snowfall: Wilmington, northern Delaware, 21.4"
  • State precipitation record for 24 hours - Vernon, central Delaware, 9/15-16/1999, 12.36"
  • State precipitation record for 1 year - Lewes, southern Delaware, 1948, 72.75"
  • State snowfall record for 24 hours - Dover, central Delaware, 2/18-19/1979, 25.0"
  • State snow record for 1 season - Wilmington, northern Delaware, 1995-1996, 59.4"
  • August 1, 2009 through January 31, 2010 was the wettest period since record-keeping began for the state 115 years ago. Delaware received 34.65 inches of precipitation, more than a foot above the average of 22.04"


Data sources: National Climatic Data Center, severe thunderstorm / tornado watch data period is 1999 - 2008, NOAA Storm Prediction Center
State lightning flash density average - 1997-2011, Vaisala, Tornado climate data - NOAA Storm Prediction Center

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