Growing Degree Day Model for the Early Growth and Development of Cereals
This heat driven early growth and development model for cereal crops is found in Early Growth and Development of Cereals (Karow, et al., 1993 ). Created jointly by Oregon State University and USDA Agricultural Research Service (ARS) scientists, it is based on cumulative growing degree days from the time of seeding.  An initial seeding depth of 2 inches was used for model prediction and the output will update automatically based on the current number of growing degree days.  This is a simple model and actual development can be affected by differences in variety, climate extremes, disease stressors and other factors.  However, under normal circumstances this model is considered fairly accurate.  The model is predictive through development of the sixth leaf, and should not be considered a substitute for checking field conditions.
PDF - Karow, et al., 1993        
(if not opening, right click and save target)  
Autoupdate: 3/6/2015        
Growing Degree Days are in farenheit using base 32 which is suitable for winter wheat.
Seeding Current Crop Year 30 Year (81-10') % of normal Plant Stage Plant Stage
Date GDD  Average GDD GDD Current Predicted 30 year Normal
09/01 2755 2298 120 Beyond 6th Leaf Beyond 6th Leaf
09/15 2340 1827 128 Beyond 6th Leaf Beyond 6th Leaf
10/01 1838 1408 131 Beyond 6th Leaf Beyond 6th Leaf
10/15 1446 1118 129 Beyond 6th Leaf 4th Leaf
11/01 1064 862 124 4th Leaf 2nd Leaf
11/15 904 703 129 3rd Leaf 2nd Leaf
12/01 771 578 133 2nd Leaf 1st Leaf