When the dew point is high, the human body struggles to cool itself through sweating. Sweat evaporates more slowly in humid conditions, making it harder to regulate body temperature. For example, a dew point above 65°F is often considered uncomfortable, while a dew point above 70°F can feel oppressive. This is why high dew points are often associated with heatwaves and can lead to heat-related illnesses if precautions are not taken.