You can now switch to display humidity as "Dew Point temperature" instead of "Relative Humidity (RH%)" from the Humidity Options screen (open by tapping on the humidity display in the app). This is available currently in Web, Android app version 2.8.16 or above, and the latest iOS app currently under AppStore review.

Relative Humidity is, like its name suggests, a relative measure of water content in the air. It is the ratio of current water content relative to the maximum water that can be dissolved.

Dew Point on the other hand, is like "absolute humidity". It indicates the temperature at which condensation forms, which is only determined by how much water is dissolved in the air currently, and is unrelated to current temperature. Dew Point is a better indicator of how humid the air actually feels.

Because the higher the temperature of the air, more water can be dissolved, if we plot RH% like our app could only do in the past, often you will see it has strong negative correlation with temperature, i.e. it just moves in the opposite direction of the temperature change, and it was hard to tell the actual change of water content in the air, or how humid the air felt.

If you switch to Dew Point display, all of a sudden, the humidity trace is decoupled from temperature change, and the water content change becomes much more clear. We can see from below plot, that as temperature rises new water is dissolved into air (for example there might have been a water puddle before the temperature rise), but the dew point reaches peak before temperature reaches its peak, indicating the water puddle is gone, or drier wind blew the water vapor away.

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