The WEATHER Act of 2023 directs the Federal Crop Insurance Corporation to research and develop a new type of insurance policy called a "single index insurance policy" that would protect farmers against income losses caused by specific weather events such as drought, excessive moisture, extreme heat, hail, wildfire, and high winds. This index-based insurance would be available nationwide across all 50 states and U.S. territories and would cover all types of crops and commodities, with flexibility for farmers to adjust their coverage levels based on their individual farm income. The bill prioritizes making the insurance accessible to small-scale and underserved farmers, reducing paperwork requirements, and processing claims quickly—within 30 days of a weather event. The Federal Crop Insurance Corporation must complete its research and report findings and recommendations to Congress within one year of the bill's enactment, though no specific funding amount is authorized in the legislation itself.