We're reading the chart the same way OK. It's what the dew point is that I think is confusing you. It's the temperature at which the amount of water that's in the air would become 100% relative humidity. Maybe it's the relative humidity that's confusing you. If you have a certain amount of water in the air at, say, 38°F and it gives you 20% RH, then, if the temperature drops to 24°F the RH would become 45%. The warmer the air the more water it can hold. The Relative Humidity is the amount of water in the air divided by the total amount it can hold expressed as a percentage. When the temperature drops to the point where the air can no longer hold that much water it precipitates out onto things. Dew. If the dew point is below 32°F it comes out as frost. Capisce?