The red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae), is the most destructive seed-feeding pest of sunflower in North America. The life history of S. fulvus (e.g., univoltine, overwintering within 6 cm of soil surface) suggests several strategies to limit crop damage, but insecticides remain the primary management tool. To facilitate broader management of S. fulvus, a degree-day model for adult emergence was developed and tested. Emergence of adults under controlled conditions produced a lower developmental threshold of 5 °C, ≈ 970 degree-days to first emergence, and ≈ 1160 degree-days to 50% emergence. Soil temperature data showed accumulated degree-days were similar 5 cm below turf and 10 cm beneath bare soil. Observed emergence of weevils in field plots occurred several days earlier than predicted (using 5 cm turf or 10 cm bare soil temperatures) when soil was kept free of vegetation. However, observed emergence was similar to predicted emergence when plots were shaded by spring wheat, which is representative of crops planted after sunflower for much of North America. Though access to soil (rather than ambient) temperature data is needed, this first degree-day model provides a tool to help growers avoid S. fulvus damage using early planting or early-maturing hybrids.