The theories regarding why people yawn range from boredom to cooling the brain to helping the brain to stay more alert. Regardless of what causes yawning, it is widely accepted that yawning is contagious.
Heat makes people sleepy because of the mechanisms the body uses to keep itself cool, lack of adjustment to warm temperatures and lack of sleep due to exposure to hot, humid nights, according to Global Bioweather. The human body takes several days to acclimate to the heat, and a person who has not acclimatized to warm weather is likely to feel sluggish. Oxygen levels and blood pressure are also lower.
The human nose contains two small, oblong bones that come together to form the bridge of the nose, according to Healthline. The rest of the nose's structure is provided by cartilage rather than bone.