Climate extreme indices are metrics and measurements that measure how often or how severe extreme weather events are in a given place. These indices are based on specific thresholds (like unusually hot days or heavy rainfall) and help scientists track trends, predict future risks, and prepare for the impacts of extreme weather, especially in the context of climate change.

In contrast, climate impact indices measure the real-world effects of climate change and extreme weather events on things like agriculture, water resources, human health, ecosystems, and the economy. They help us understand how climate change is affecting people's lives and the environment, and they provide crucial information for planning and adapting to future climate risks.

In simple terms, climate extreme indices will tell you how hot it gets in a region, while climate impact indices will tell you how that heat is affecting crop yield, human health, or water supply in that region.