Landscape and Nursery - Frost/Freeze Data

We have had several frosts now in the mid-state area in Delaware. The following are tables of frost freeze data from NOAA (National Oceanic and Atmospheric Administration) for DE and recent low temperatures from the Dover weather station. Landscapers and nursery personnel can use the NOAA table to advise clients on the likelihood of first frost and last frost in the state.

Click on tables for larger images.

Frost/freeze probabilty table.

Frost/freeze probabilty table closeup.

Dover area October high and low temperatures since the first frost. You read the table as follows: Date, Average Temperature (F), High Temperature, Time of High, Low Temperature, Time of Low.

Landscape - First Significant Fall Frost Across Mid State on Monday Night

The first significant fall frost occurred across parts of midstate on Monday morning. The frost was heavy enough to affect many annual flowers, some perennials, and a smaller number of trees and shrubs. The following are the lows on Monday morning, October 20, 2008 (in degrees F):

Harrington 30.1
Smyrna 30.5
Blackbird 30.5
Dover 28.8
Viola 27.9
Sandtown 28.6
Ellendale 31.9

Dieback in annual vinca from the frost. Note the winter annual broadleaf weeds in the background that were not affected. They will not go cold dormant until a heavy freeze. Click on picture for a larger image.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County