Question 1

What is the dew point?

Accepted Answer

The dew point is the temperature at which air becomes saturated and water vapor begins to condense into dew, fog or clouds. A higher dew point means more moisture in the air. Unlike relative humidity, the dew point directly measures absolute moisture content.

Question 2

What formula does this calculator use?

Accepted Answer

This tool uses the August-Roche-Magnus formula: γ = ln(RH/100) + (a·T)/(b+T), Td = (b·γ)/(a−γ), with constants a = 17.625 and b = 243.04°C, accurate to within ±0.4°C across the normal temperature range.

Question 3

What dew point is comfortable?

Accepted Answer

Dew points below 55°F (13°C) feel dry and comfortable. Between 55–60°F (13–16°C) the air starts to feel humid. Above 65°F (18°C) most people find it oppressive and muggy, and above 70°F (21°C) it is dangerously humid.

Question 4

How is dew point different from relative humidity?

Accepted Answer

Relative humidity tells you how close the air is to saturation as a percentage, which changes with temperature. Dew point is an absolute measure of moisture that stays the same regardless of temperature, so it is a more reliable indicator of how humid the air actually feels.

Dew point comfort reference