Enjoy the outdoors? Practicing your yoga and qigong outdoors in the summer is a wonderful way to enjoy and connect to nature. To best take advantage I suggest avoiding the extreme heat of the day. Practice in the early morning and late evening. Find a shady spot. If possible practice your yoga and qigong by the water for it's cooling effects.
Remember your body is constantly working toward homeostasis. If you are feeling overheated help out and include postures that are closer to the ground for a cooling effect. Try some slow, flowing movements to release the back like Little Boat, Little Boat Twist and Bridge. Stretch and release your body while laying on the ground. Leg stretches can replace more demanding standing postures. I suggest leaving the intense flows for another day.
Slow, gentle exhales can be cooling and calming. Practice a few in Savasana or in a comfortable seated position. A slow and mindful qigong session with a focus on gentle exhales can also have a cooling effect. Be aware of how your body responds and adjust accordingly.
As temperatures rise so can tempers, irritability and annoyance. A mindfulness meditation can help to recognize reactive behavior and put it into perspective. Everyone is hot and bothered. What can you do to help the situation?