Heat in Delaware, July 23 to 31, 1999

A run of consecutive days with high temperatures in the 90s started in Delaware on July 23rd. It lasted as long as 16 days in some areas through August 7th. Dispersed within this run were two periods of both excessive heat and humidity: from July 23rd through July 25th and again from July 29th through August 1st. A cold front moved through the area on the 25th and brought in drier air. High temperatures still reached into the 90s from the 26th through the 28th. The humidity and even higher temperatures returned on the 29th. A strong cold front moved through the region the afternoon and evening of August 1st. This brought in considerably drier air, the driest air since mid July. Because of the extremely dry ground conditions, high temperatures kept reaching around 90 degrees through the 7th. That day a stronger cold front brought in a cooler air mass from Canada into the northeastern United States. Delmarva hospitals reported a few cases of heat related injuries. The continued excessive heat and lack of rain parched non-irrigated farms across the state. For most places the highest temperatures during this hot spell occurred on the 23rd and 31st. They included 99 degrees in Milford (Kent County), 98 degrees at the New Castle County Airport and 96 degrees in Georgetown (Sussex County). Shore areas had some relief from the heat as seabreezes developed along the shore. The hottest days along the shore were the 25th, 28th and August 1st.