Dew Point Calculator
Input temperature and relative humidity to find the exact Dew Point, the most accurate metric for weather "mugginess" and human comfort.
Dew Point Evaluator
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Understanding Dew Point vs Relative Humidity
When reading a weather forecast, most people look at "Relative Humidity" to gauge how muggy the air will feel. However, meteorologists heavily prefer Dew Point. Why? Because Dew Point is an absolute measure of moisture in the air, whereas Relative Humidity is exactly that—relative.
The Problem with Relative Humidity
Warm air can hold significantly more water vapor than cold air.
A freezing winter day with 10% humidity and a hot 90°F summer day with 10% humidity actually contain vastly different amounts of water in the air. Furthermore, if you take 50°F air at 100% humidity and heat it up to 80°F (without adding any water), the relative humidity plunges to around 35%. The amount of water didn't change, but the percentage did!
What is Dew Point?
The Dew Point accurately describes the exact temperature to which air must be cooled to become fully saturated (100% relative humidity). If air cools past its dew point, water vapor condenses out of the air, forming morning dew on grass, fog in valleys, or frost on your windshield.
The Human Comfort Scale
Because humans cool themselves by sweating, high moisture in the air prevents sweat from evaporating efficiently. You can use Dew Point as an absolute gauge for "mugginess":
- Below 55°F (12°C): Pleasant and comfortable. The air is dry.
- 55°F to 60°F (13°C - 16°C): Sticky border. Most folks find it comfortable but noticeable.
- 60°F to 65°F (16°C - 18°C): Muggy. Noticeably moist and sticky.
- 65°F to 70°F (18°C - 21°C): Oppressive. Very uncomfortable for most individuals.
- Above 70°F (21°C): Miserable. Sweating is largely ineffective at cooling the body.