The purpose of this paper is to advance smart contract-based crop insurance. The research question is: How can season-ahead forecasting be implemented to adjust the premiums on smart-contract-based hydroclimate-extreme insurance? The progression of this paper will be as follows: First, blockchain technology will be summarized. Then, a versatile crypto-currency, Ethereum, will be presented to implement hydroclimate-extreme insurance. Finally, three case studies will be presented- two in southern Africa, Zimbabwe and Lesotho, and one in Australia. Season-ahead forecasting will be used to determine when premiums for crop insurance should increase due to increased probability of hydroclimate-extremes.