This handbook is intended to assist agricultural extension workers in the Philippines in their efforts to collaborate with farmers so that the latter can make more informed decisions on agricultural activities. Specifically, this Handbook aims to (1) increase the understanding of the nature and implications of seasonal climate forecast, (2) determine the value of seasonal climate forecast in agriculture, and (iii) develop the skills of resource managers in the use of seasonal forecasts to manage climate variability. By providing guidance through agricultural extension workers, the handbook seeks to empower farmers to make informed farm production decisions, thereby improving productivity and agricultural sustainability.