Climate variability in West Africa threatens agricultural productivity and food security. This work evaluates Growing Degree Days (GDD) and BBCH phenological stages as a decision-support approach for six strategic crops: maize, early millet, lablab, bongolom, melon and watermelon. Thermal thresholds were identified under controlled conditions to support crop diversification, fertilization, irrigation, harvest planning and pest management. The resulting decision-support tools provide farmers in The Gambia and Cape Verde with a practical and low-cost method to improve climate resilience and resource-use efficiency.