This step-by-step manual describes procedures for climate change adjustments relative to extreme rainfall and local sea level estimates. The principles presented are based on worked examples discussed in the knowledge product accompanied by this manual. While the overall approach on climate change adjustment procedures and calculations are intended to be as transparent as possible, key sources of information and assumptions are open to scrutiny as some elements may be affected by rapid advancements in science and technology. It is essential for data to be periodically reviewed, in line with the latest reports from the Intergovernmental Panel on Climate Change.