Hi Miya,
There is more information and comments about some of the different methods that can be used to help cool down the tendency of any memory foam to sleep warmer for some people in post #6 here but memory foam manufacturers don’t disclose their specific formulations and there are so many variables involved in temperature regulation other than the memory foam formulation itself that the only way to know whether any memory foam mattress in combination with all the other variables that can affect temperature regulation will be “temperature regulating enough” for you will be based on your own personal experience.
While cashmere (and the silk that they use in the quilting) are natural fibers that like other natural fibers can help with temperature regulation in both directions … in most cases the amount of cashmere is a cover fabric is relatively small. I don’t know the percentage of cashmere in their cover fabric or whether the silk in the quilting is blended with other fibers as well.
Again though … the mattress protector or sheets you use can either add to or diminish the temperature regulating effect of the cover and quilting materials and the memory foam underneath it.
Phoenix