"Temperature extremes" refers to the very hot or very cold points on a scale. It describes the high and low points of temperature, where it is either extremely hot or extremely cold. Full definition
That leads to different patterns of temperature extremes in different places at different times. (wxshift.com)
It is imperative that they be protected from temperature extremes at all times, and that they always have access to fresh water and shade. (bulldoghavennw.org)
Plus, these dogs don't do well with temperature extremes. (aplaceforanimals.com)