Temperature requirements for bud development after a rest period (breaking rest) from maximum rest to end of rest were determined to develop an empirical model for predicting rest development in terminal vegetative buds of red-osier dogwood (Cornus sericea L.). One-year-old plants at maximum rest were exposed to temperatures from 5 to 20 °C a 12 h photoperiod (SD) in growth chambers. Depth of rest was measured by days to bud break in either 16 h photoperiod (LD) or natural daylength at 20/15 °C/night temperature. Developmental stages during rest development were expressed by degree growth stage (°GS).Chilling was effective breaking rest after plants attained maximum rest (270 °GS). Development during rest (breaking rest) increased with decreasing temperature. No significant development occurred at 20 °C. Rate of rest development (°GS h⁻¹) at all temperatures varied during the breaking rest period and depended on developmental stage (°GS). A °GS model described and quantified rest development (°GS). Using temperature and developmental stage, the model predicted end of rest (315°GS) within 3 days and daily rest development (°GS) in both years.