Various shades of brown
Blood drying out (Yin Def with heat).
The more heat, the more viscous/less liquid the flow.
Could also be old blood – often as the uterus is not positioned correctly
Correct life imbalances esp improve diet by eating more protein, veggies and fat.
Rest and exercise and sunshine in proportion.
Check out BBT to see if your thyroid is working well
Iodine and iron may be needed.