In the cool of morning, yoga practices refresh and awaken me. Later on when I’m teaching, it will be hot enough to warrant the use of the cooling breath.  During deep winter, we utilize the fire bellows breathing. 
Adapting and adjusting our practices to the presence circumstances empowers us daily to be flexible not just in the hamstrings. Yoga offers tools for every situation.  While mouth breathing is generally ill advised, doing so consciously with the tongue either behind the teeth or rolled into a straw will allow cooler heads to prevail.
Which yoga practices appeal to you in the heat? Which do you select in the cold? Ki to Happiness chooses practices to balance and harmonize with the ever changing present reality.