How does dew point affect humidity

In fact, the heat index temperature — what it actually feels like outside — would be 98 degrees! We can see from these examples that the closer the temp is to the dew point, the higher the relative humidity. The farther apart they are the lower the relative humidity. The general rule of thumb is that dew points in the 50s or lower is comfortable during the warm months.

Dews above 65 are downright muggy and even tropical when they reach the 70s. Customize Your Weather. Privacy Policy. Dew Point vs Humidity Weather. Current Hazards. Local Radar. Rivers and Lakes. Climate and Past Weather. The relative humidity is not an exact ratio between the current air temperature and dewpoint! Instead of checking the humidity on such days, one should focus on the dewpoint and the resulting heat index to determine how sticky it will feel outside.

The heat index utilizes temperature and dewpoint or relative humidity to determine how hot the body perceives the environment. Because the body cools down through the evaporation of sweat, moist air will not allow evaporation as readily as dry air. Once the air temperature cools below its dew point, water vapor in the atmosphere will condense. This causes the relative humidity to go up and down like a roller coaster during the day. The relative humidity will go up at night when the air temperature approaches the dew point, and the relative humidity will go down as the air temperature warms farther and farther away from the dew point during the day.

This consistency allows us to index the dew point to comfort levels, giving us a quick understanding of how muggy or pleasant it is outside.