Issue 5, June 22, 2022

Modified Growing Degree Days June 21

Modified Growing Degree Days (Base 50⁰ F, March 1 through June 21)

Station Location Actual Total Historical Average   (11 year) One- Week Projection
Freeport 940 867 1071
St. Charles 948 837 1083
DeKalb 946 862 1082
Monmouth 1149 1024 1292
Peoria 1156 1070 1304
Champaign 1230 1121 1388
Springfield 1275 1247 1432
Perry 1261 1173 1418
Brownstown 1476 1153 1642
Belleville 1420 1336 1588
Rend Lake 1542 1428 1714
Carbondale 1501 1359 1677
Dixon Springs 1511 1386 1686

Insect development is temperature dependent. We can use degree days to help predict insect emergence and activity. Home, Yard, and Garden readers can use the links below with the degree day accumulations above to determine what insect pests could be active in their area.

GDD of Landscape Pests
GDD of Conifer Pests

Degree day accumulations calculated using the Pest Degree-Day Calculator Calculator (a project by the Department of Crop Sciences at the University of Illinois and the Illinois Water Survey).

Return to table of contents