When I look at Arabian Peninsula and the Sahara as AR6 regions with CMIP-6, SSP 5-8.5, Change, Annual, for Days Over 40o C, I get big numbers - an increase of 50-80 days over 40o by 2100.
When I create a user-defined box within those regions, and even when I create a user-defined box that tracks the entire Arabian Peninsula, and specify exactly the same parameters, I get 8-10 days of change in Days Over 40o C. Am I doing something wrong in setting up a user-defined box? Seems pretty straightforward.