Recognizing that the changing climate is a significant threat to the health of our communities, the Association of State and Territorial Health Officials (ASTHO) has created this toolkit to help state and territorial health agencies enhance their climate readiness, program by program. The toolkit offers practical steps for integrating climate readiness into seven public health topic areas: air quality, water safety, vector-borne and zoonotic disease, food safety, chemical safety, healthy sustainable communities and injury prevention, and natural disaster emergency preparedness. Worksheets have been provided throughout the toolkit to assist readers in performing Climate Readiness Assessments in each topic area.